AP Statistics Review
What should be the height of the missing bar in the histogram? 75 0.7 70 60 50
75
Test scores are normally distributed with a mean of 72 and a standard deviation of 4.2. What is the percentile of a score of 65. -90th percentile -85th percentile -95th percentile -5th percentile -1st percentile
5th percentile
If SAT scores are normally distributed with a mean of 500 and a standard deviation of 100, what minimum score is needed to ensure that you are in the top 7%? * 640 500 645 650 648
648
Which statement is true? * -A simple random sample should not be used in an experiment -Descriptive statistics are graphs such as scatter plots or histograms -Inferential statistics are used to estimate population parameters -Regression and correlation are used to describe a single variable. -Parameters are no different from statistics
Inferential statistics are used to estimate population parameters
What is the probability that you and your friend choose the same number between 1 and 20? * .5 .05 .0025 .053 .005
.05
The average weight of men between the ages 40-49 is 202.3 pounds with a standard deviation of 50.7 pounds. Find the probability that a man in this age group is under 180 pounds if it is known that the distribution is approximately normal. * .6700 .6331 .3301 .3300 .3669
.3300
In the standard normal distribution, what is the probability that z ≥ 1.25? * 0.8925 0.8962 0.8944 0.1056 0.1038
0.1056
A binomial random variable X counts the number of successes in 50 trials. If μx = 20, what is the probability of success for a single trial? * 0.4 0.84 0.6 0.16 The probability of success cannot be determined from the given information
0.4
Suppose that X is a binomial random variable that counts the number of successes in 12 trials. Find P(X ≤ 3) if the probability of success for a single trial is 0.29. * 0.1807 0.2460 0.2775 0.4765 0.5235
0.4765
Suppose that X is a binomial random variable that counts the number of successes in 30 trials. Find P(X > 1) if the probability of success for a single trial is 0.14. * 0.0108 0.0529 0.0638 0.9362 0.9892
0.9362
A score at or above the 90th percentile is how many standard deviations from the mean? -1.28 above the mean -1.64 above the mean -2.58 above the mean -1.28 below the mean -1.64 below the mean
1.28 above the mean
A coin is weighted so that the probability of heads if 0.64. On average, how many coin flips will it take for tails to first appear? * 1.56 2 2.78 6.4 This cannot be determined
1.56
Consider the following table. What is the probability of a sum of two or nine when a fair four-sided die and a fair five-sided die are rolled? 1/10 2/25 1/8 2/9 2/5
1/10
A binomial experiment has n = 50 trials. The probability of failure for each trial is 0.4. Let X be the count of successes of the event during the 50 trials. What are μx and σX? * 30; 12 20; 12 30; 3.5 20; 3.5 It is not possible to find with the given information
30; 3.5
In a normal distribution, approximately what percentage of the data is within one standard deviation of the mean * -32% -68% -65% -64% -34%
68%
Identify the situation where you would conduct an experiment * -A baseball fan wishes to determine who is the best pitcher in Major League Baseball -A farmer wants to study the yields of three varieties of peas developed by Monsanto, Burpee, and Heirloom. -A doctor want to maintain a complete record of medical information on each patient. -A poll is conducted to determine the proportion of people cheating on their federal income tax. -An educator wishes to determine the average IQ of students of students in the New Tech Program
A farmer wants to study the yields of three varieties of peas developed by Monsanto, Burpee, and Heirloom.
Choose the statement below that describes the use of inferential statistics. * -By Assessing the coloration and state of health of 195 pigeons, they found that darker pigeons had lower concentrations of a blood parasite called haemosporidian." -The average age of students in AP Biology is 16.5 years. -The average grade of Test 3 in the Spring Semester Algebra course was 63%. -The US Department of Ed. data from 2007 - 2008 found that KIPP charter schools received $12,731 per student. -The standard deviation of the pain scores from a Tylenol treatment group was 1.25
By Assessing the coloration and state of health of 195 pigeons, they found that darker pigeons had lower concentrations of a blood parasite called haemosporidian."
We say that the design of a study is biased if which of the following is true? * -Certain outcomes are systematically favored -None of the above. -A racial or sexual preference is suspected -The correlation is greater than 1 or less than -1 -Random placebos have been used
Certain outcomes are systematically favored
You are testing a new medication for relief of depression. You are going to give the new medication to subjects suffering from depression and see if their symptoms have lessened after a month. You have eight subjects available. Half of the subjects are to be given the new medication and the other half a placebo. The names of the eight subjects are given below. Using the list of random digits, starting at the beginning of this list and using single-digit labels, you assign the first four subjects selected to receive the new medication, while the remainder receive the placebo. The subjects assigned to the placebo are -Blumenthal, Costello, Duvall, and Fan. -Blumenthal, House, Pavlicova, and Tang -House, Long, Pavlicova, and Tang. -Costello, Duvall, Fan, and Long. -Costello, House, Duvall and Long
Costello, Duvall, Fan, and Long
Calculate the expected value and the variance of the following probability distribution. E(X) = 2.0, Var = 1.4 E(X) = 2.1, Var = 1.0 E(X) = 2.1, Var = 1.2 E(X) = 2.1, Var = 1.4 E(X) = 2.0, Var = 1.0
E(X) = 2.1, Var = 1.4
The probability distribution for the number of incidents occurring in a year is shown below. Calculate the expected value and the variance. E(X)=2.0, Var=1.0 E(X)=1.9, Var=1.8 E(X)=2.0, Var=1.8 E(X)=2.0, Var=1.4 E(X)=1.9, SD=1.4
E(X)=2.0, Var=1.8
Which of the following statements best describes probability? I. 0 ≤ P(E) ≤ 1 II. The sum of the probabilities of all possible outcomes is 1 III. The probability of an event is the ratio of successes to failures * I only I and III only II only I and II only III only
I and II only
For the probability density curve below, which of the following statements is true? I. The area is exactly 1 underneath it II. It does not model the distribution of the model III. It is a function that is always positive -I and III only -II and III only -II only -III only -I only
I and III only
Which of the statements is true about outliers I. They are natural variation but rare II. They indicate that something may be wrong with the data collection process III. They are not important and should be identified and the ignored -II only -III only -I only -II and III only -I and III only
II and III only
Which statement is true about standard deviation? I. It is typically reported with the median II. It measures the spread of the data set III. It is not resistant to extreme values -I only -I and III only -II and III only -II only -III only
II and III only
Which of the statements is true about observational studies? I. They impose treatments on subjects. II. The researcher does not attempt to manipulate a response. III. The researcher wishes to determine an effect from a treatment. * -I only -I and III only -I and II only -II only -III only
II only
Which of the statements is true about the necessary conditions for using the normal probability distribution? I. If μ = 0 and σ = 1, you know that the distribution is normal. II. The normal distribution can be used at any time regardless of a population's distribution. III. When it is known that a distribution is approximately normal, the normal distribution may be used. * I only I and II only I and III only II only III only
III only
Find the intercept from the least square regression line for the data below of final grade as a percent and days absent. What does it tell you about the relationship? -Intercept is approximately 94.695. For no absences, the student's predicted grade is about 94.695%. -Intercept is approximately 94.965. For no absences, the student's predicted grade is about 94.965. -Intercept is approximately 6.767. For no absences, the student's predicted grade is about 67.67%.
Intercept is approximately 94.695. For no absences, the student's predicted grade is about 94.695%.
The scatter plot of study time in hours versus test scores is shown below. What can be said about the relationship between time spent studying and test scores? -More time spent studying is related to lower test scores -Less time studying is required to higher test scores -More time studying is related to higher test scores -Higher test scores are caused by more time studying -There is no discernible relationship between study time and test scores.
More time studying is related to higher test scores
Individual outcomes of a random experiment are called _________. * Events Random variables Experimental Results Experimental findings Sample Space
Sample Space
At the Westminster Dog Show, sponsors wish to measure the popularity of the booths in the retail area. Using a list of all attendees, a random number is generated to determine a starting position in the list, and then every tenth attendee is placed in the sample. When the end of the list is reached, sampling continues from the top of the list. Sampling stops when the starting position is reached. Which of the following methods was used to select the probability sample? * -Random -Systematic -Stratified -Cluster -Simple Random
Systematic
A large population has a distribution that is heavily skewed to the right with a mean of 10 and a standard deviation of 2.5. If all possible samples of size 45 are taken, which of the following statements will be true about the distribution of sample means? * -The distribution will be approximately normal with a mean of 10 and a standard deviation of 2.5 -The distribution will be skewed to the right with a mean of 10 and a standard deviation of 2.5 -The shape cannot be determined, but the mean will be 10 with a standard deviation of 2.5 -The distribution will be skewed right with a mean of 10 and a standard deviation of 0.37 -The distribution will be approximately normal with a mean of 10 and a standard deviation of 0.37
The distribution will be skewed right with a mean of 10 and a standard deviation of 0.37
Which of the following is not a random variable? * The roll of a fair die The temperature in Vancouver, BC The number of votes for different candidates in an election The number of minutes in an hour The heart rates of patients in Long Beach Memorial Hospital
The number of minutes in an hour
Using the data set, what can be said about the relationship between earnings and dividends? More earnings are related to less dividends Fewer earnings are related to more dividends There is no discernible relationship between earnings and dividends More dividends are cause by more earnings More earnings are related to more dividends
There is no discernible relationship between earnings and dividends
Which of the following is an example of continuous data? * -Number of foreclosures in Las Vegas each month -Number of heartbeats per minute -Number of Netflix DVDs returned each day -Number of contacts you have on your cell phone -Value of the New York Stock Exchange (NYSE) composite index each day at closing
Value of the New York Stock Exchange (NYSE) composite index each day at closing
Local schools wish to add a bond measure to the ballet. They survey the residents with the following question: "Will you support the bond measure if it will cost the taxpayers $30 million in 30 years?" Three-fourths of respondents reply "No." Which type of sampling bias best describes the situation? * -Voluntary Response -Wording -Response -Researcher -Non-response
Wording
Find the number of data values represented and the median for the stem plot below. -n = 20; median: 36.56 -n = 24; median: 32 -n = 20; median: 34 -n = 13; median: 34 -n = 13; median: 36.5
n = 20; median: 34
The pie chart shows the number of respondents to a survey that asked how many trips they made to the supermarket last week. By reconstructing the frequency distribution, find the mean and standard deviation of the number of trips made to the supermarket. -x= 3.2, s= 0.5 -x= 3.0, s= 1.03 -x= 3.0, s= 1.0 -x= 108.0, s= 0.3 -x= 21.6, s= 0.5
x= 3.0, s=1.0
From the data, find the least square regression line. What type of correlation is there? y= -299.5+4.375x. There is no discernible relationship y= -299.5+4.375x. There is a negative linear correlation y= 299.5-4.375x. There is a negative linear correlation y= -299.5+4.375x. There is a positive linear correlation
y= -299.5+4.375x. There is a positive linear correlation
What is the probability of drawing a king or a queen, given that you have already drawn two kings and two queens and have not replaced them? * 1/12 1/26 1/13 2/25 0.08
1/12
What is the probability of drawing a queen from a deck of cards, given that you have already drawn two kings and two queens and have not replaced them? * 1/52 1/26 1/48 1/24 0.038
1/24
Consider the following table. What is the probability of a sum of five when a fair four-sided die and a fair five-sided die are rolled? 4/25 1/4 1/5 4/5 4/9
1/5
What is the probability of rolling at least one six on a pair of fair dice? 11/36 1/3 1/6 1/15 1/16
11/36
From the regression output below, what percentage of the variation is unexplained? 87.1% 85.5% 32.6% 12.9% All the variation is explained
12.9%
Which statement is true of the data set summarized by this five-number summary? -anything greater than 10.5 is an outlier -There are no outliers -3 and 20 are both outliers -20 is an outlier -3 is an outlier
20 is an outlier
In a normal distribution, approximately what percentage of data is more than 2 standard deviations SMALLER than the mean? * -2.5% -95% -0.15% -5% -97.5%
2.5%
Consider the following table. What is the probability of rolling at least one three when a fair four-sided die and a fair five-sided die are rolled? 9/20 2/5 8/25 1/2 4/9
2/5
The cumulative frequency distribution of airfares is displayed in the o-give. What airfare corresponds to the 20th percentile, the 50th percentile, and the 80th percentile. -20th= 95, 50th=102, 80th=106 -20th= 96, 50th=103, 80th=106 -20th= 96, 50th=102, 80th=106 -20th= 96, 50th=102, 80th=100 -20th= 96, 50th=102, 80th=107
20th= 96, 50th=102, 80th=106
A binomial experiment has n = 75 trials. The probability of success for each trial is 0.3. Let X be the count of successes of the event during the 75 trials. What are μx and σX? * 22.5; 15.75 22.5; 3.97 52.5; 15.75 52.5; 3.97 It is not possible with the given information
22.5; 3.97
What is the probability that a single card drawn from a standard deck of cards (jokers removed) will be a jack or a heart? * 15/52 1/52 4/221 17/52 4/13
4/13
The distribution of5,250 standardized test scores is normal with a mean of 258 and a standard deviation of 10. Approximately how many scored between 248 and 278? * -4279 -1785 -3570 -709 -4988
4279
What are the mean and the standard deviation of a binomial experiment that occurs with probability of success of 0.3 and is repeated 150 times? * 45; 5.6 45; 31.5 105; 5.6 105; 31.5 It is not possible to find with the given information
45; 5.6
In a litter of five puppies, what is the probability of getting two males and three females, assuming an even chance for each gender? * 1/32 0.031 1/16 5/16 1/4
5/16
In a litter of five puppies, what is the probability of getting two males and three females or three males and two females, assuming an even chance for each gender? * 0.063 1/16 5/16 5/8 1/2
5/8
What data point is indicated on the distributions? Mean: 67.0 Standard Deviation: 5.1 -67.0 -64.5 -61.9 -77.2 -72.1
72.1
Suppose we classify 315 randomly selected college students according to their general major field and their self-described political viewpoint. The table presents the results. Which of the following list of numbers is a marginal distribution of the variable political viewpoint? -30, 20, 18 -91, 116, 108 -85, 90, 72, 68
91, 116, 108
The average weight of men between the ages 20-29 is 188.3 pounds with a standard deviation of 66.4 pounds. The average weight of women between the ages 20-29 is 155.9 pounds with a standard deviation of 60.3 pounds. If it is known that the distributions are approximately normal, which of the statements is true? I. A woman weighing 215 pounds is more likely than a man weighing 255 pounds. II. A man weighing 255 pounds is more likely than a woman weighing 215 pounds. III. They are equally likely. * I only I and II only I and III only II only III only
I only
From the regression output and scatter plot, find r. How would you classify the strength of this relationship? r=0.924. There is a strong negative linear relationship. r=0.961. There is a strong positive linear relationship. r=0.924. There is a strong positive linear relationship. r=-0.924. There is a strong negative linear relationship. r=-0.961. There is a strong negative linear relationship.
r=-0.961. There is a strong negative linear relationship.
If the difference between a treatment and control group is too big to attribute to chance, it is ______________________. * statistically significant not significant important a maximum substantial
statistically significant
Suppose a cell phone company manufactures cell phones and tablets in the following four states: Arizona, California, Washington, and Minnesota. The table below shows the percentage of total output by state, and within each state, the percentage output of each product. What is the probability that a randomly selected product will be a tablet manufactured in Minnesota? (Assume that all products are shipped from one distribution center.) 0.05 0.08 0.004 0.5 0.04
0.004
An experiment consists of 31 independent trials. The probability that any one trial is a failure is 45%. Which is the best estimate of the probability that more than 20 trials will be failures? * 0.01 0.02 0.11 0.89 0.99
0.01
Consider a binomial random variable X that counts the number of successes in 100 trials. If μX = 15, find the probability of exactly 21 successes in the 100 trials. * 0.973 0.027 0.098 0.902 The probability cannot be determined from the given information
0.027
A random variable X counts the number of successes in 16 independent trials. The probability any one trial is successful is 0.2. What is the probability of exactly five successful trials? * 0.2 0.88 0.8 0.92 0.12
0.12
A binomial experiment consists of 12 repeated trials. If the probability that the first success occurs on the second trial is 0.25, what is the probability of exactly 7 successful trials? * 0.25 0.75 0.19 0.01 The probability cannot be determined from the given information
0.19
The probability that any one trial out of 23 independent trials will be successful is 17%. Find the probability that fewer than three trials will be successful. * 0.43 0.15 0.22 0.56 0.78
0.22
A binomial random variable X counts the number of successes in 40 trials. If μx = 30, what is the probability of failure for a single trial? * 0.75 0.25 0.56 0.44 The probability of failure cannot be determined from the given infromation
0.25
A score at or above the 70th percentile is how many standard deviations from the mean? -0.52 above the mean -1.04 below the mean -1.64 above the mean -0.52 below the mean -1.04 above the mean
0.52 above the mean
The probability of Bill serving an ace in tennis is 0.15, and the probability that he double faults is 0.25. What is the probability that Bill does not serve an ace or a double fault? * 0.5 0.15 0.4 0.9 0.6
0.6
The number of successes in ten trials is counted by the binomial random variable X. If the probability that the fifth trial is successful is 0.8, what is the probability the sixth trial will be a success? * 0.09 0.12 0.64 0.2 0.8
0.8
In the standard normal distribution, what is the probability that -2.95 < z ≤ 0.95? * 0.0016 0.8289 0.8305 0.8273 0.8276
0.8273
Which of the following best describes a chance experiment? * An activity where we can observe but cannot predict outcomes Playing a game of poker Measuring the miles per gallon of a vechicle Picking a number between 1 to 10 Picking a multiple choice problem without a clue.
An activity where we can observe but cannot predict outcomes
What is an appropriate method for performing randomization? * -Appropriately using a table of random digits to select participants or assign treatment -Haphazardly generating a list of digits to select participants or assigned treatment -Using telephone numbers as random digits to select participants or assign treatments -Using a complicated math function to select participants or assign treatments -Rearranging the digits to select participants or assign treatments
Appropriately using a table of random digits to select participants or assign treatment
What would be an appropriate way to assign digits in order to simulate flipping an unfair coin with P(H) = 0.3? * Assign digits 1,2,3 to be a head. Assign 4 - 9 to be a tail. Assign digits 0,1,2,3 to be a head. Assign 4 - 9 to be a tail. Assign digits 0,1,2,3 to be a tail. Assign 4 - 9 to be a head. Assign digits 0,1,2 to be a tail. Assign 3 - 9 to be a head. Assign digits 0,1,2 to be a head. Assign 3 - 9 to be a tail
Assign digits 0,1,2 to be a head. Assign 3 - 9 to be a tail
Which of the following statements best describes the scatter plot? I. A linear model would fit the data well II. The bivariate data are positively correlated III. The linear relationship is weak I only I and III only I and II only II only III only
I and II only
In the histogram below, which of the following statements is true (Data is on the left side) I. The mean is greater than the median II. The mean is less than the median III. The data set includes large outliers -II and III only -II only -I and III only -III only -I only
I only
Which of the following represents the probability that someone who works full time has more than $5,000 in credit card debt? * P(Full time and credit card debt over $5000) P(Full time or credit card debt over $5000) P(Full time | credit card debt over $5000) P(Credit Card debt over $5000 | Full Time) P(Full time)*P(Credit Card debt over $5000)
P(Credit Card debt over $5000 | Full Time)
The random variable X represents the number of successes in 10 independent trials. Which of the following represents the probability of fewer than two failures? * P(x≤2) P(x<2) P(x>8) p(x≤8) The probability of success for an individual trial must be known to determine which of these represents the probability.
P(x>8)
A credit card company wishes to sample its customers to find out which features of the rewards program are preferred. Its call center schedules calls between 5:30 and 8:00 P.M. Only 25% of the customers the call center reaches are willing to participate. Which type of sampling bias best describes the situation? * -Voluntary Response -Wording -Response -Researcher -Non-Response
Non-Response
The average body mass index value of children 9 years old is 18.4 with a standard deviation of 4.5. If it is known that the distributions are approximately normal, what is the index for children at the 82nd percentile? * 22.6 22.0 23.0 0.92 0.82
22.6
A population of unknown shape has a mean of 25 and a standard deviation of 3.4. What is the mean and the standard deviation of the sampling distribution of sample means when n = 16? * 25; 0.85 25; 3.4 6.25; 0.85 6.25; 3.4 The mean and standard deviation cannot be found since the sample size is small
25; 0.85
The distribution of the binomial random variable that counts the number of successful trials in 65, each of which have a 30% probability of success, can be approximated by which of the following distributions? -A slightly skewed left distribution with a mean of 65 and a standard deviation of 19.5 -A slightly skewed left distribution with a mean of 19.5 and a standard deviation of 3.7 -An approximately normal distribution with a mean of 65 and a standard deviation of 19.5 -An approximately normal distribution with a mean of 19.5 and a standard deviation of 3.7 -The number of trials is not large enough to make a determination
An approximately normal distribution with a mean of 19.5 and a standard deviation of 3.7
A further study of habits and test scores is conducted. One variable of interest is the number of hours that students spent on the internet in the weeks before the exam. From the data, find the least square regression line. What type of correlation is there? -Test Score= 95.494+4.508(Internet Time). There is a positive linear correlation. -Test Score= 4.508+95.494(Internet Time). There is a positive linear correlation. -Test Score= -95.494-4.508(Internet Time). There is a negative linear correlation. -Test Score= 95.494-4.508(Internet Time). There is a negative linear correlation. -Test Score= 4.508-95.494(Internet Time). There is a negative linear correlation.
Test Score= 95.494-4.508(Internet Time). There is a negative linear correlation.
A zoologist studying adult bears measures a number of different variables. Which of the following possible variables is categorical? -the level of aggression (low, moderate, high) displayed by an adult bear -The number of fish an adult bear eats in a particular day. -the weight in pounds of an adult bear
the level of aggression (low, moderate, high) displayed by an adult bear
A random variable X counts the number of successes in 20 independent trials. The probability that any one trial is unsuccessful is 0.42. What is the probability of exactly eight successful trials? * 0.17 0.05 0.52 0.08 0.42
0.05
In a statistics course, the probability that a randomly selected student has taken a calculus course is 0.14, while the probability that a randomly selected student drives to campus is 0.48. If the two events are independent, what is the probability that a randomly selected student in this statistics course has taken a calculus course and drives to campus? * 0.07 0.14 0.34 0.48 0.62
0.07
Suppose a cell phone company manufactures cell phones and tablets in the following four states: Arizona, California, Washington, and Minnesota. The table below shows the percentage of total output by state, and within each state, the percentage output of each product. What is the probability of selecting at random a cell phone made in California or Arizona while you are shopping for a phone? (Assume that all products are shipped from one distribution center.) 0.191 0.130 0.631 0.447 0.808
0.631
The average height of women between the ages 30-39 is 163.2 centimeters with a standard deviation of 9.3 centimeters. Find the probability that a woman in this age group is over 160 centimeters if it is known that the distribution is approximately normal. * 0.3669 0.3655 0.6331 0.6360 0.3660
0.6331
The dataset below is based on a survey of 100 randomly selected travelers who were asked, "How many trips per year do you typically take?" What is the probability that a randomly selected traveler is a male or takes 2 or fewer trips per year? 0.17 0.18 0.36 0.69 0.86
0.69
The number of successes in 15 trials is counted by the binomial random variable X. If the probability that the third trial is a failure is 0.3, what is the probability the fourth trial will be successful? * 0.7 0.3 0.22 0.13 0.09
0.7
Given the following probability distribution, find P (1 ≤ X ≤ 4). 0.01 0.08 0.20 0.58 0.70
0.70
A binomial random variable X counts the number of successes in n trials. What are the mean and standard deviation of X if the probability of failure is 0.29 and is repeated 145 times? * 42.05; 5.46 102.95; 5.46 42.05; 29.86 102.95; 29.86 It is not possible to find with the given information
102.95; 5.46
What is the probability of drawing a jack first and a three second from a standard deck of cards (jokers removed), when two cards are drawn without replacement? * 1/169 2/13 16/663 2/663 1/338
16/663
Choose an example below that is an example of descriptive statistics. -Joe randomaly sampled 10 pages of his thesis and counted 6 typographical errors. He concluded that there are 30 typographical errors in his entire 50 - page theses. -A study suggests, based on samples, that glaciers have lost volume of average ten to 100 times faster in the last 30 years compared to other time periods. -Belleville's IT department extrapolated from evidence provided by teachers regarding the number of mathematical errors in the curriculum that students grades should be increased by 4%. -A government report on broadband access in the United States indicated that the mean broadband speed (mbps) is 12.1 mbps -A random sample of surnames in Milan, Italy, showed that 32% were Torino. The study concluded that 32% of all people in Milan had the last name Torino.
A government report on broadband access in the United States indicated that the mean broadband speed (mbps) is 12.1 mbps
The histogram represents the heights of males in the United States between the ages of 20-29. The mean is 69.6 inches and the standard deviation is 2.6 inches (approx Normal). Three adult males are selected from the group. Their heights are 75 inches, 63 inches, and 79 inches. Determine which heights, if any, are unusual. -The 79 inch height is the only one that is unusual because it is more than 3 standard deviations above the mean. The z-scores, respectively, are: 2.08, -2.54, and 3.62. -The 79 inch height and the 63 inch height are unusual since they are more than 2 standard deviations from the mean. The z-scores, respectively, are: 2.00, -2.54, and 3.62. -All heights are unusual since they are more than 2 standard deviations above the mean. The z-scores, respectively, are: -2.08, -2.54, and 3.62. -All heights are unusual since they are more than 2 standard deviations above the mean. The z-scores, respectively, are: 2.08, -2.54, and 3.62.
All heights are unusual since they are more than 2 standard deviations above the mean. The z-scores, respectively, are: 2.08, -2.54, and 3.62.
The distribution of the binomial random variable that counts the number of successful trials in 70, each of which have a 40% probability of failure, can be approximated by which of the following distributions? * -A slightly skewed right distribution with a mean of 28 and standard deviation of 16.8 -A slightly skewed right distribution with a mean of 42 and a standard deviation of 4.1 -An approximately normal distribution with a mean of 28 and a standard deviation of 16.8 -An approximately normal distribution with a mean of 42 and a standard deviation of 4.1 -The number of trials is not large enough to make a determination
An approximately normal distribution with a mean of 42 and a standard deviation of 4.1
From the regression output below, which type of variation does R-squared (R-Sq) pertain to? Coefficient of determination Sum of the residuals squared Correlation coefficient Total variation Standard Error
Coefficient of determination
Of the three lines shown below, which module would result in the largest residual. I only II only III only I and II have points with the same residual as that residual is larger than any residual seen in III. I, II, III all have a point with the same large residual.
II only
Which of these statements is true about continuous random variables and their probability distributions? I. The distribution is modeled by a probability distribution function that is non-negative. II. The probability of an individual event E is calculated by P(X = E). III. The total area under the curve is 1. * I only I and II only I and III only II only III only
I and III only
Which of the statements is true about the normal probability distribution? I. μ = 0 and σ = 1 only. II. It is symmetric about μ with tails extending to positive and negative infinity. III. The total area under the curve cannot be determined because the tails are asymptotic to the horizontal axis. * I only I and II only I and III only II only III only
II only
Which of these statements is true about the law of large numbers? I. One hundred trials will be enough to determine the true proportion in the population. II. Over time the proportion of successes in a simulation approaches the true proportion in the population. III. The relative frequency of successes from just a few trials accurately approximates the true probability of success. * I only I and II only II only I and III only III only
II only
Of the three lines graphed below, which is the best fitting? Why? II because it has the least sum of squares III because it has the least sum of squares II because it has the most sum of squares I because it has the most sum of squares III because it has the most sum of squares
III because it has the least sum of squares
Which of the plots of a correlation coefficient approximately equal to 0.9? I only II only I and II only III only II and III only
III only
Students in a biomedical statistics course take two tests before a final. The statistics from the first test for three different classes (May, June, and July) are shown. What would be the average and the standard deviation of the sum of the test scores? Mean of the Sum: 51. Standard deviation:10.51 Mean of the Sum: 51. Standard deviation:5.45 Mean of the Sum: 51. Standard deviation:3.24 Mean of the Sum: 51. Standard deviation:2.33 Mean of the Sum: 50. Standard deviation:3.24
Mean of the Sum: 51. Standard deviation:3.24
In the residual plot below, is the particular point an overestimate, underestimate, or neither? Overestimate because y-y<0 Underestimate because y-y>0 Neither Underestimate because y-y<0 Overestimate because y-y>0
Overestimate because y-y>0
Find the slope of the least square regression line for the data below of final grades as a percent and days absent. What does this tell you about this relationship? -Slope is approximately 6.767. For each additional day absent, the student final grade increases about 6.767% -Slope is approximately -94.695. For each additional day absent, the student final grade decreases about 0.947%. -Slope is approximately -6.767. For each additional day absent, the student final grade decreases 6.767%
Slope is approximately -6.767. For each additional day absent, the student final grade decreases 6.767%
In the scatter plot, what effect does the indicated point have on the correlation coefficient and the slope of the least square regression line. The point is influential, r decreases and the slope increases The point is influential, r decreases and the slope decreases The point is influential, r decreases and the slope is unaffected The point is not influential, r and the slope are unaffected The point is influential, r and the slope are unaffected
The point is influential, r decreases and the slope increases
Which of the following is not a characteristic of stratified sampling? * -This method can improve the represetativeness of the sample by -insuring that subpopulations are represented. -The Strata are mutually exclusive -Persons from each and every strata are chosen to be in the sample -Randomization plays a role -The population is divided into heterogeneous groups called strata
The population is divided into heterogeneous groups called strata
It is known that 80% of the items in a population have a given property. If all possible samples of size 60 are taken from this population, which of the following would describe the sampling distribution of the sample proportion of items with the given property? -The sampling distribution is skewed right with a mean of 0.8 and a standard deviation of 0.31 -The sampling distribution is skewed left with a mean of 0.1 and a standard deviation of 0.05 -The sampling distribution is approximately normal with a mean of 0.8 and a standard deviation of 0.05 -The sampling distribution is approximately normal with a mean of 0.1 and a standard deviation of 0.31 -The conditions are not met to make any statement about the sampling distribution
The sampling distribution is approximately normal with a mean of 0.8 and a standard deviation of 0.05
A researcher is interested in the cholesterol levels of adults in the city in which she lives. A free cholesterol screening program is set up in the downtown area during the lunch hour. Individuals can walk in and have their cholesterol levels determined for free. One hundred and seventy three people use the service, and their average cholesterol is 217.8. The sample obtained is an example of * -a multistage sample of varying cholesterol levels. -a sample probably containing bias and undercoverage. -a simple random sample, since the experimenter did not know beforehand which individuals would come to the screening. -a stratified sample of high and low cholesterol individuals. -a systematic random sample
a sample probably containing bias and undercoverage.
From the data below, find the least square regression line. What type of correlation is there? y= 24.765-9.051x. There is a negative linear correlation. y= 24.765+9.051x. There is a positive linear correlation. y= 9.051+24.765x. There is a positive linear correlation. y= 9.051-24.765. There is a negative linear correlation. y= -24.764-9.051x. There is a negative linear correlation.
y= 24.765+9.051x. There is a positive linear correlation.
In a litter of five puppies, what is the probability of not getting two males and three females or three males and two females, assuming an even chance for each gender? * 3/8 5/8 1/2 11/16 0.038
3/8
The histogram represents the heights of males in the United States between the ages of 20-29. The mean is 69.6 inches and the standard deviation is 2.6 inches. Since the heights are approximately normal, find the height that represents the 20th percentile. How should this be interpreted? -60 inches. 20% of the population of males between 20 - 29 are shorter than approximately 60 inches. -68.6 inches. 20% of the population of males between 20 - 29 are shorter than approximately 68 inches. -67.4 inches. 20% of the population of males between 20 - 29 are shorter than approximately 68 inches. -67.4 inches. 20 males between 20 - 29 are shorter than approximately 67 inches. -60 inches. 20 males between 20 -29 are shorter than approximately 60 inches tall.
67.4 inches. 20% of the population of males between 20 - 29 are shorter than approximately 68 inches.
Data values represented by the bar labeled "10" in the histogram below -8.5 up to 11.5 -8.75 up to 11.25 -8.75 up to 11.75 -7.5 up top 12.5 -7.25 up top 12.75
8.75 up to 11.25
The mean rate for cable with internet from a sample of households was $106.50 per month with a standard deviation of $3.85 per month. Assuming that the data set is normal, estimate the percent of the households with rates from $100 to $115. -94% -3.2% -49% -99% -6.4%
94%
A nutritionist wants to study the effect of storage time (6, 12, and 18 months) on the amount of vitamin C present in freeze dried fruit when stored for these lengths of time. Vitamin C is measured in milligrams per 100 milligrams of fruit. Six fruit packs were randomly assigned to each of the three storage times. The treatment, experimental unit, and response are respectively: * -A specific storage time, amount of vitamin C, a fruit pack -A fruit pack, amount of vitamin C, a specific storage time -Random assignment, a fruit pack, amount of vitamin C -A specific storage time, a fruit pack, amount of vitamin C -A specific storage time, the nutritionist, amount of vitamin C
A specific storage time, a fruit pack, amount of vitamin C
We've come a long way since Morse code, with text messaging now the most rapidly developing form of communication, especially among the younger generations. An AP Statistics student in a large high school plans to survey his fellow students with regard to their preference among various text messaging styles. Which of the following survey methods would result in an unbiased result? * -The student comes to school early and surveys the first 100 students who arrive -The student posts the survey on her Facebook page, asking everyone to respond -The student passes a survey card to every student, with instructions to fill it out at home and drop the filled out card in a box by the school entrance the next day -The student goes to all the high school sporting events for a week, hands out the survey, and waits for each student to fill it out and hand it back -All of the above would lead to biased results
All of the above would lead to biased results
A zoologist studying adult bears measures a number of different variables. One variable is the body temperature of the bear during hibernation. Which of the following is the best description of the distribution of this variable. -The geographical area in which the adult bears can be found. -All the values that the zoologist records for body temperature and how many individual -The difference between the highest temperature recorded for a bear's body temperature and the lowest
All the values that the zoologist records for body temperature and how many individual
Choose the statement below that best describes the parameter. * -The standard deviation of the age of students attending community college based on 10 representatives from each campus -Average concentration of latic acid in 30 samples of cheddar cheese from Wobegon, WI. -Gallop poll on "life evaluation" shows 53% "thriving" and 44% "struggling. -Proportion of wrinkled peas in a sample collected in an organic garden -Average salary of all professors at The University of Michigan.
Average salary of all professors at The University of Michigan.
In the histogram below, which of the following statements is true (Data is on the right side) I. The mean is greater than the median II. The mean is less than the median III. The data set includes small outliers -I only -I and III only -II and III only -III only -II only
II only
A charter school operator in Los Angeles wishes to gather information about student achievement. From the 73 small schools the operator manages, one school is selected by lottery, and all students from that school are used in the sample. Which of the following methods was used to select the probability sample? * -Random -Systematic -Stratified -Cluster -Simple Random
Cluster
Suppose you have an unfair die, one weighted so that the even numbers have twice the probability of showing as the odd numbers. Complete the probability distribution. Which statements are true? * I. The distribution cannot be determined II. 1/9, 2/9, 1/9, 2/9, 1/9, 2/9 III. This is a continuous distribution I only I and III only I and II only II only III only
II only
Which of the following best describes random variables? I. 0 ≤ P(E) ≤ 1 II. A value, discrete or continuous, that is assigned as an outcome of a random experiment III. A value, never continuous, that is an outcome of a random experiment * I only I and III only II only I and II only III only
II only
Find the correct measure of center from the data set below. Which measure of center would be appropriate measure to use for each? Why? -Data sets 1 and 2 both have Means at 6.2. They should use the mean for both since there are no outliers. -Data set 1: Mean of 6.2. Use the mean because there are no outliers. Data set 2: Median 5.5. Use the median because 15 is an outlier. -Data set 1: Median 7. Use the median because there are no outliers. Data set 2: Mean 6.2: Use the mean because 15 is an outlier. -Data set 1 and 2 both have Median at 6.2. They should use the median because both 10 and 15 are considered outliers. -Data set 1 and 2 both have a mean of 6.2. They should use the mean because 10 and 15 are outliers.
Data set 1: Mean of 6.2. Use the mean because there are no outliers. Data set 2: Median 5.5. Use the median because 15 is an outlier.
A research dermatologist is considering two experimental designs to compare the efficacy of treating the common wart. Patients ages 6 to 16, each with two facial warts, will be enrolled in the study. Design 1 involves flipping a coin as each patient enters the office, and if heads, treating both warts with duct tape applied directly to the warts, and if tails, treating both warts with liquid nitrogen cryotherapy. Design 2 involves flipping a coin as each patient enters the office, and if heads, treating the larger wart with duct tape and the smaller with cryotherapy, and if tails, reversing the order. With both designs, warts are measured at baseline and then at a return visit. Which of the following is accurate? * -Neither designs uses randonization since there is no indication that patients will be randomly picked from the population of all wart sufferers. -Design 1 is a completely randomized design while design 2 is a block design -Both designs use blinding, but neither use a placebo -In the second design, duct tape treatment and cryotherapy treatments are confounded. -One of the two designs is actually an observational study, while the other is an experiment.
Design 1 is a completely randomized design while design 2 is a block design
A researcher randomly selected 50 online teachers to participate in a study on the effects of multitasking. Before the study began, teachers completed a survey that was used to determine a baseline rage index. Then the researcher randomly assigned teachers to one of two groups. One group was allowed to perform tasks such as grading assignments, responding to email, and teaching classes in one-hour intervals, while the other group had to perform tasks whenever they were received or demanded, with priority given to students requesting tutoring. After a period of one month, teachers again completed the survey to measure their rage index. Which of the statements describes this study? I. This is an experiment. II. This is an observational study. III. This is a matched-pairs design. * I only I and III only II only I and II only III only
I and III only
Which of the statements is true about a double-blind experiment? I. Subjects are not aware whether they are receiving viable treatments. II. It is a study of adolescent-onset blindness. III. Researchers are not aware of the distribution of placebos or viable treatments. * -I only -I and III only -I and II only -II only -III only
I and III only
A researcher wishes to study the effects of diet on weight loss. He recruits 60 overweight subjects to participate in the study and records their gender. He also randomly assigns three different diet and exercise regimens to the subjects. Which of the following describes appropriate blocking techniques? I. Block on gender II. Block on diet III. Block on exercise * I only I and III only II only I and II only III only
I only
In general, which of the following do researchers attempt to achieve when designing experiments? I. Attempt to impose statistical control II. Attempt to replicate an observational study III. Attempt to randomize events * -I only -I and III only -I and II only -II only -III only
I only
Which of the statements is true about the placebo effect? I. It is a response due to believing that a treatment is being administered. II. It is an effect from a legitimate treatment. III. It is a negative response due to a high dosage. * -I only -I and III only -I and II only -II only -III only
I only
Which of the statements is true about blocking? I. Treatments are organized in the same way between blocks. II. They are used to replicate treatments on the same subject. III. Treatments are randomized within blocks. * I only I and III only I and II only II only III only
III only
Find the mean and median in the dot plot below (n = 20) -Mean 12.9; median 13.5 -Mean 12.4; median 14 -Mean 12.4; median 13 -Mean 12.9; median 13 -Mean 12.9; median 14
Mean 12.9; median 13.5
Which of the following measures the center of a distribution? * -Standard deviation -Mean and median -Correlation coefficient -Interquartile range and range -Variance
Mean and median
The frequency distribution shows the number of magazine subscriptions per household in a random sample (n=50). Find the mean number of subscriptions per household. -Mean: 2.0 -Mean: 1.8 -Mean: 1.5 -Mean: 3.0 -Mean: 92
Mean: 1.8
Using the data set, calculate the mean and standard deviation. {3, 8, 10, 3, 12, 7, 10} * -Mean: 7.5; St. Dev: 3.5 -Mean: 7.6; St. Dev: 12.3 -Mean: 8.0; St. Dev: 4.0 -Mean: 7.6; St. Dev: 3.5 -Mean: 7.6; St. Dev: 4.0
Mean: 7.6; St. Dev: 3.5
A random sample of households and the number of cars per household are shown below. What is the BEST estimate of the sample mean? - Mean= 1 -Mean= 2 -Mean= 2.5 -Mean=3 -Mean=27
Mean= 2
Which measure of center is most resistant to extreme values? * -Mean -Interquartile range -Range -Standard deviation -Median
Median
Choose the five-number summary that matches this stem plot. -Min: 13; Q1: 23; Med: 27; Q3: 34; Max: 51 -Min: 13; Q1: 22.5; Med: 27; Q3: 33.5; Max: 51 -Min: 13; Q1: 23; Med: 26; Q3: 34; Max: 51 -Min: 13; Q1: 22.5; Med: 26; Q3: 33.5; Max: 51 -Min: 13; Q1: 23; Med: 27; Q3: 33.5; Max: 51
Min: 13; Q1: 23; Med: 27; Q3: 34; Max: 51
Find the five-number summary from the box plot and calculate the interquartile range. -Min: 3; Q1: 5.75; Med: 10.5; Q3:13.75; Max 16; IQR: 8 -Min: 3; Q1: 5.75; Med: 9.5; Q3: 13.75; Max 15; IQR: 8 -Min: 4; Q1: 5.75; Med: 9.5; Q3:13.75; Max 16; IQR: 8 -Min: 3; Q1: 5.75; Med: 9.5; Q3:13.75; Max 16; IQR: 9 -Min: 3; Q1: 5.75; Med: 9.5; Q3:13.75; Max 16; IQR: 8
Min: 3; Q1: 5.75; Med: 9.5; Q3:13.75; Max 16; IQR: 8
In a normally distributed data set with a mean of 13 and a standard deviation of 2, if the data are standardize by subtracting by the mean and dividing by the standard deviation, which of these statements best describe the resulting distribution? -Normal with a mean of 6.5 and a standard deviation of 1 -Normal with a mean of 0 and a standard deviation of 2 -Normal with a mean of 0 and a standard deviation of 1 -Normal with a mean of 13 and a standard deviation of 2 -Normal with a mean of 6.5 and a standard deviation of 2
Normal with a mean of 0 and a standard deviation of 1
A linguist studies conversation styles by gender and age to assess differences between gender. The data was collected by studying videotapes made of "best friends" who were asked to have conversation together. Which choice best describes the type of study that was conducted? * -Observational -Census -Experimental -Poll -Survey
Observational
The mathematics department wishes to form a sample from each of 10 courses offered. They randomly select three individuals from each course and include them in the 30-person sample. Which of the following methods was used to select the probability sample? - -Random -Systematic -Stratified -Cluster -Simple Random
Random
Consider an experiment to investigate the effectiveness of different insecticides in controlling pests and their effects on subsequent yield. What is the best reason for randomly assigning treatment levels (spraying or not spraying) to the experimental units (farms)? * -Randomization makes the analysis easier since the data can be collected and entered into the computer in any order. -Randomization is required by statistical consultants before they will help you analyze the experiment. -Randomization implies that it is not necessary to be careful during the experiment, during data collection, and during data analysis -Randomization makes the experiment easier to conduct since we can apply the insecticide in any pattern rather than in a systematic fashion. -Randomization will tend to average out all other uncontrolled factors such as soil fertility so that they are not confounded with the treatment effects.
Randomization will tend to average out all other uncontrolled factors such as soil fertility so that they are not confounded with the treatment effects.
Researchers studied the effects that improving vision with eyeglasses had on educational outcomes. They identified 2069 students who could improve their vision with eyeglasses. 750 were not offered glasses and 1319 were. Of the 1319 offered eyeglasses, 928 accepted eyeglasses. Students who received the eyeglasses scored significantly higher in both math and science. What was the treatment in this study? * -Scoring significantly higher in math. -Not receiving eyeglasses -Being identified as a student whou could improve -Recieving eyeglasses -Being offered eyeglasses
Recieving eyeglasses
To study the relationship between two variables, what type of graph would you use? * -Dot Plot -Histogram -Stem Plot -Scatter Plot -Cumulative Frequency Plot
Scatter Plot
The frequency distribution shows the number of magazine subscriptions per household in a random sample (n=50). Find the standard deviation for the number of subscriptions per household. -St. Dev: 1.5 -St. Dev: 3.0 -St. Dev: 2.3 -St. Dev: 2.0 -St. Dev: 1.2
St. Dev: 1.5
Which of the following measures the spread of the data? * -Mean -Median and Interquartile range -First and third quartile -Standard deviation and variance -Correlation coefficient
Standard deviation and variance
Identify the situation where you would conduct a survey * The US Army wants to find the average cost of training a cadet. -A pharmaceutical company wants to advertise that its pain killer is more effective that aspirin, ibuprofen, and Tylenol. -A gambler wishes to calculate the expected value of buying two lottery tickets. -Stanford researchers want to determine the effects of improving student vision has on learning. -Gallop wishes to determine the proportion of people who see themselves as thriving
Stanford researchers want to determine the effects of improving student vision has on learning.
At a charter high school, administrators wish to collect a sample of 50 students. The proportions of the student body represented by each class are: 45% freshmen, 28% sophomores, 16% juniors, and 11% seniors. They decide to randomly sample 23 freshmen, 14 sophomores, eight juniors, and five seniors. Which of the following methods was used to select the probability sample? * -Random -Systematic -Stratified -Cluster -Simple Random
Stratified
What common sampling technique involves considering the population of interest as a collection of non-overlapping groups and selecting from each of these groups? -Cluster sampling -Random Sampling -Systematic Sampling -Stratified sampling -Representative Sampling
Stratified sampling
Choose the statement below that describes the use of inferential statistics. -The proportion of belonging to the union is approx. 98% according the National Education Association. -The Median Home price of $328, 221 in Long Beach California, taken from 50 homes selected randomly from the Multiple Listing Service (MLS) -The Volatility of the New York Stock Exchange went from -$34.23 to $297.19 on March 3rd, 2013. -THe proportion of subcompact cars in the Michigan reported over 30 Miles per Gallon (MPG) in city driving -The tallest student was 6'7" at Canton Prep High School
The Median Home price of $328, 221 in Long Beach California, taken from 50 homes selected randomly from the Multiple Listing Service (MLS)
The data set of water consumption for a small town in gallons per day is listed below. What is the effect on the mean and standard deviation if consumption is increased by 50 gallons per day? (166, 179, 193, 175, 144, 151, 173, 175, 177, 160, 195, 225, 240, 144, 162, 145, 177, 163, 149, 188). -The mean will increase by 59 and the standard deviation will change by the square root of 50. -The mean and standard deviation increase by 50. -The mean will increase by 50. The standard deviation remains the same. -The mean remains the same. The standard deviation increases by 50. -The mean and standard deviation stay the same.
The mean will increase by 50. The standard deviation remains the same.
Which of the following describes a random variable * -The grade earned on an exam by a student -The weight of a gallon of water. -The price of crude oil on the commodities market on April 1, 1984. -The number rolled on a fair die -The time required by Mr Lang to run a marathon.
The number rolled on a fair die
Why is randomization commonly used when selecting a sample? * -So that only data relevant to the values in interest collected -To allow computers to aid in the process -To aid in calculations of sample statistics -So that the sample is not taken from a group that is not related to the question of interest -To avoid bias from being introduced
To avoid bias from being introduced
In which of the following situations would it be most DIFFICULT to use a census? -To determine what proportion of homes in a small town have garages -To determine what proportion of students at a high school get driven to school by their parents. -To determine what proportion of teachers at a given high school like their job -To determine what proportion of sharks in the oceans are great white sharks -To determine what proportion of Major League Baseball teams are east of the Mississippi River.
To determine what proportion of sharks in the oceans are great white sharks
In a statistics course, the instructor wishes to determine whether a new program for statistical analysis would be beneficial to students. He asks for 10 volunteers from the class to use the program in their final project and provide feedback regarding ease of use. Which of the following methods was used to select the nonrandom sample? * -Simple Random -Convience -Statified -Cluster -Voluntary Response
Voluntary Response
Street parking in your neighborhood is limited. You have amassed 10 parking tickets in one year and believe your neighbors have had a similar experience. You leave 50 postcards on the windshields of parked cars in your neighborhood asking for a response to one question with room for additional comments. You receive 48 responses, and 30 of the responses include elaborate descriptions of street parking issues. Which type of sampling bias best describes the situation? * -Voluntary response -Wording -Response -Researcher -Non-Response
Voluntary response
in 2007 Forest Whitaker won the Best Actor Oscar at age 45. Helen Mirren won the Best Actress Oscar at 61. The age distribution of actors who won the Oscar is approximately normal with and average of 42.5 with a standard deviation of 7.6. The age distribution of actresses is also approximately normal with the average age at 35 with a standard deviation of 9.7. Find the z score for each. What statement describes the results? * -Whitaker: z =-0.33; Mirren: z = 2.68. Whitaker's age was about average and Mirren's age was well above average -Whitaker: z =0.33; Mirren: z = -2.68. Whitaker's age was well above average and Mirren's age was well below average -Whitaker: z =0.33; Mirren: z = 2.68. Whitaker's age was about average and Mirren's age was well above average -Whitaker: z =0.33; Mirren: z = 2.68. Whitaker's age was well above average and Mirren's age was about average -Whitaker: z =2.68; Mirren: z = 0.33. Whitaker's age was well above average and Mirren's age was about average
Whitaker: z =0.33; Mirren: z = 2.68. Whitaker's age was about average and Mirren's age was well above average
A researcher randomly selected 50 overweight volunteers to participate in a study on weight and energy consumption. Each volunteer's weight and metabolic rate were recorded. Then the researcher randomly assigned the subjects to one of two groups. One group received a metabolism-boosting supplement, and the other group received a placebo. Neither the subjects nor the researcher knew who received the treatment or the placebo. This is an example of * an observational study a double blind study a completely randomized experiment an experiment a block experiment
a double blind study
A television station is interested in predicting whether voters in its viewing area are in favor of federal funding for abortions. It asks its viewers to phone in and indicate whether they support/are in favor of or are opposed to this. Of the 2241 viewers who phoned in, 1574 (70.24%) were opposed to federal funding for abortions.Referring to the information above, the viewers who phoned in are -a probability sample. -a census -a voluntary response sample. -a population. -a convenience sample
a voluntary response sample.
A marketing research firm wishes to determine if the adult men in Laramie, Wyoming, would be interested in a new upscale men's clothing store. From a list of all residential addresses in Laramie, the firm selects a simple random sample of 100 and mails a brief questionnaire to each. The population of interest is * -the 100 addresses to which the survey was mailed. -upscale men's clothing stores -all residential addresses in Laramie, Wyoming. -all adult men in Laramie, Wyoming. -the members of the marketing firm that actually conducted the survey.
all adult men in Laramie, Wyoming.
Can pleasant aromas help a student learn better? Two researchers believed that the presence of a floral scent could improve a person's learning ability in certain situations. They had 22 people work through a pencil-and-paper maze six times, three times while wearing a floral-scented mask and three times wearing an unscented mask. The three trials for each mask closely followed one another. Testers measured the length of time it took subjects to complete each of the six trials. They reported that, on average, subjects wearing the floral-scented mask completed the maze more quickly than those wearing the unscented mask, although the difference was not statistically significant. This study is * -a convenience sample -a double blind experiment -a voluntary response sample -an observational study -an experiment
an experiment
A researcher randomly selected 50 volunteers to participate in a study on weight and energy consumption. Each volunteer's weight and metabolic rate were recorded. This is an example of ______________________. * an observational study a double blind experiment a completely randomized experiment an experiment a block experiment
an observational study
In order to assess the opinion of students at the University of Minnesota on campus snow removal, a reporter for the student newspaper interviews the first 12 students he meets who are willing to express their opinion. In this case, the sample is -the 12 students interviewed. -reporters at the student newspaper -all those students favoring prompt snow removal. -all students at the University of Minnesota. -all students at universities receiving substantial snow.
the 12 students interviewed.
A sample space is ___________________________. * the set of experimental events from a number of trials the set of all events from a random experiment the set of all experimental findings the set of all the experimental results the set of all possible outcomes of a random experiment
the set of all possible outcomes of a random experiment
A study of human development showed two types of movies to groups of children. Crackers were available in a bowl, and the investigators compared the number of crackers eaten by children watching the different kinds of movies. One kind of movie was shown at 8 AM (right after the children had breakfast) and another at 11 AM (right before the children had lunch). It was found that during the movie shown at 11 AM, more crackers were eaten than during the movie shown at 8 AM. The investigators concluded that the different types of movies had an effect on appetite. The results cannot be trusted because * -the study was not double-blind. Neither the investigators nor the children should have been aware of which movie was being shown. -the investigators should have used several bowls, with crackers randomly placed in each. -the investigators were biased. They knew beforehand what they hoped the study would show. -children do not eat crackers while watching movies -the time the movie was shown is a confounding variable.
the time the movie was shown is a confounding variable.
Steve's test grade was 84. The class average was 72 and the standard deviation was 4.5. What statement best describes his z score? * -z = -2.67. Compared to the rest of the class, Steves grade is low. -z = -1.67. Compared to the rest of the class, Steves grade is a little below average. -z = 2.67. Compared to the rest of the class, Steves grade is a little above average. -z = 1.67. Compared to the rest of the class, Steves grade is a little above average. -z = 2.67. Compared to the rest of the class, Steves grade was high.
z = 2.67. Compared to the rest of the class, Steves grade was high.
