stats exam final
The following data are the yields, in bushels, of hay from a farmer's last 10 years: 375, 210, 150, 147, 429, 189, 320, 580, 407, 180. Find the IQR.
227
The colors of book covers on a bookshelf
qualitative
the native languages of students in an English class
qualitative
the number of calls received at a company's help desk
quantitative
the temperatures of cups of coffee served at a restaurant
quantitative
The ____________ variable is the variable whose value can be explained by the _____________ variable.
response; predictor
The coefficient of determination is the _______________ of the linear correlation coefficient.
square
Numbered disks are placed in a box and one disk is selected at random. There are 6 red disks numbered 1 through 6, and 7 yellow disks numbered 7 through 13. In an experiment a disk is selected, the number and color noted, replaced, and then a second disk is selected. Is this an example of independence? Answer yes or no.
yes
Using a standard deck of 52 playing cards are the events of getting an ace and getting a jack on the card drawn mutually exclusive? Answer yes or no.
yes
Find the z-score for the value 66, when the mean is 51 and the standard deviation is 1.
z=15.00
Calculate the linear correlation coefficient for the data below.
Put data into calc - R = answer (make sure to round)
Find the z-score for which the area under the standard normal curve to its right is 0.70.
-0.53
Find the z-score for which the area under the standard normal curve to its left is 0.09.
-1.34
Given the equation of a regression line , what is the best predicted value for y given x = 2.3?
-12.75
Which of the following cannot be the probability of an event?
-61
Suppose a brewery has a filling machine that fills 12 ounce bottles of beer. It is known that the amount of beer poured by this filling machine follows a normal distribution with a mean of 12.16 ounces and a standard deviation of 0.04 ounce. Find the probability that the bottle contains fewer than 12.06 ounces of beer.
0.0062
Suppose a brewery has a filling machine that fills 12 ounce bottles of beer. It is known that the amount of beer poured by this filling machine follows a normal distribution with a mean of 12.36 ounces and a standard deviation of 0.04 ounce. Find the probability that the bottle contains between 12.26 and 12.32 ounces.
0.1525
The coefficient of correlation between x and y is r = 0.59. Calculate the coefficient of determination . Round to the nearest hundredth
0.35
The probability that a region prone to hurricanes will be hit by a hurricane in any single year is 1/10. What is the probability of a hurricane at least once in the next 5 years?
0.40951
Suppose a brewery has a filling machine that fills 12 ounce bottles of beer. It is known that the amount of beer poured by this filling machine follows a normal distribution with a mean of 12.14 ounces and a standard deviation of 0.04 ounce. Find the probability that the bottle contains more than 12.14 ounces of beer.
0.5
For a standard normal curve, find the z-score that separates the bottom 70% from the top 30%.
0.53
The events A and B are mutually exclusive. If P(A) = 0.7 and P(B) = 0.1, what is P(A or B)?
0.8
A human gene carries a certain disease from the mother to the child with a probability rate of 30%. That is, there is a 30% chance that the child becomes infected with the disease. Suppose a female carrier of the gene has five children. Assume that the infections of the five children are independent of one another. Find the probability that at least one of the children get the disease from their mother. Round to the nearest thousandth.
0.832
Find the area under the standard normal curve to the left of z = 1.5.
0.9332
Recently, the stock market took big swings up and down. A survey of 993 adult investors asked how often they tracked their portfolio. The table shows the investor responses. What is the probability that an adult investor tracks his or her portfolio daily? Express your answer as a simplified fraction and as a decimal rounded to three decimal places.
223/993 = 0.238
Find the sample standard deviation. 1, 2, 3, 4, 5
1.6
Numbered disks are placed in a box and one disk is selected at random. If there are 6 red disks numbered 1 through 6, and 2 yellow disks numbered 7 through 8, find the probability of selecting a disk numbered 3, given that a red disk is selected.
1/6
Compute the range for the set of data. 51, 146, 30, 105, 164
134
The following data represent the living situation of newlyweds in a large metropolitan area and their annual household income. What percent of people who live with family make between $35,000 and $50,000 per year
15.5%
The following data represent the living situation of newlyweds in a large metropolitan area and their annual household income. Find the marginal frequency for newlyweds who rent their home
219
Given the following five-number summary, find the interquartile range 29 37 50 66 94
29
Compute the range for the set of data. 30, 37, 14, 44, 57
43
The scores from a state standardized test have a mean of 80 and a standard deviation of 10. The distribution of the scores is roughly bell shaped. Use the Empirical Rule to find the percentage of scores that lie between 60 and 80.
47.5%
Given the following five-number summary, find the first quartile. 2.9 5.7 10.0 13.2 21.1
5.7
Given the following five-number summary, find the IQR. 2.9 5.7 10.0 13.2 21.1
7.5
A probability experiment is conducted in which the sample space of the experiment is S = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15}. Let even A = {6, 7, 8, 9} and event B = {8, 9, 10, 11, 12}. Assume that each outcome is equally likely. List the outcomes in A and B. Are A and B mutually exclusive?
8&9 no
The percentage of measurements that are below the 88th percentile is
88%
There are 40 chocolates in a box, all identically shaped. There are 15 filled with nuts, 16 with caramel, and 9 are solid chocolate. You randomly select one piece, eat it, and then select a second piece. Find the probability of selecting a solid chocolate candy followed by a nut candy.
9/104
1. A hypothesis test is a "two-tailed" if the alternative hypothesis contains a ____________ sign.
=/
What is a closed question? What is an open question?
A closed question has fixed choices for answers, whereas an open question is a free-response question.
Designed Experiment
A researcher get involved in the experiment by changing the value of the explanatory variable
Define factor. Choose the correct answer below.
A variable whose effect on the response variable is to be assessed by the experimenter
Confounding Variable part 2
An explanatory variable that was considered in a study whose effect cannot be distinguished from a second explanatory variable in the study
Lurking variable
An explanatory variable that was not considered in a study, but affects the value of the response variable in the study.
Which is a measure of dispersion?
B) Standard deviation C) Variance D) Range
Find the area under the standard normal curve to the right of z = 1.
COMPLIMENT RULE! - 0.1587
If two events have no outcomes in common they are said to be
Disjoint
True or False: A doctor wishes to determine the relationship between a male's age and that male's total cholesterol level. He tests 200 males and records each male's age and that male's total cholesterol level. The males cholesterol level is the explanatory variable?
False
True or False: Variance is the square root of standard deviation.
False
Is there a relationship between the raises administrators at State University receive and their performance on the job? A faculty group wants to determine whether job rating (x) is a useful linear predictor of raise (y). Consequently, the group considered the straight-line regression model, . Using the method of least squares, the faculty group obtained the following prediction equation, . Interpret the estimated slope of the line.
For a 1-point increase in an administrator's rating, we estimate the administrator's raise to increase $2,000.
Explain the difference between a single-blind and a double-blind experiment.
In a single-blind experiment, the subject does not know which treatment is received. In a double-blind experiment, neither the subject nor the researcher in contact with the subject knows which treatment is received.
An unusual event is an event that has a
Low probability of occurrence
If the graph of a distribution of data shows that the graph is symmetric then the
Mean is a better measure of central tendency
A bag contains 25 wooden beads. The colors of the beads are red, blue, white, green, black, brown, and grey. The probability of randomly selecting a bead of a particular color from the bag is given below. Is this a probability model? Answer yes or no.
No
Distinguish between nonsampling error and sampling error
Nonsampling error is the error that results from undercoverage, nonresponse bias, response bias, or data-entry errors. Sampling error is the error that results because a sample is being used to estimate information about a population.
Which of the following probabilities for the sample points A, B, and C could be true if A, B, and C are the only sample points in an experiment?
P(A) = 0, P(B) = 1/15, P(C) = 14/15
The null and alternative hypotheses are given. Determine whether the hypothesis test is left-tailed, right-tailed, or two-tailed and the parameter that is being tested. 1. H0 : p = 0.94 H1: p > 0.94
Right-tailed, p
Given a distribution that follows a standard normal curve, what does the graph of the curve do as z increases in the positive direction?
The graph of the curve approaches zero
A history instructor has given the same pretest and the same final examination each semester. He is interested in determining if there is a relationship between the scores of the two tests. He computes the linear correlation coefficient and notes that it is 1.15. What does this correlation coefficient value tell the instructor?
The history instructor has made a computational error.
Define response variable. Choose the correct answer below.
The quantitative or qualitative variable for which the experimenter wishes to determine how its value is affected by the explanatory variable
observational study
The researcher will only observe and will not attempt to influence the outcome of the study
The class width is the difference between
Two successive lower class limits
If we reject the null hypothesis when the null hypothesis is true, then we have made a
Type I error
confounding variable
a factor other than the independent variable that might produce an effect in an experiment
A researcher determine that the linear correlation coefficient is 0.85 for a paired data set. This indicates that there is
a strong positive linear correlation
A recent study attempted to estimate the proportion of Florida residents who were willing to spend more tax dollars on protecting the Florida beaches from environmental disasters. Thirty-one hundred Florida residents were surveyed. Which of the following is the population used in the study?
all Florida residents
A small computing center has found that the number of jobs submitted per day to its computers has a distribution that is approximately bell shaped, with a mean of 76 jobs and a standard deviation of 7. Where do we expect most (approximately 95%) of the distribution to fall?
between 62 and 90 jobs per day
Classify the statement as an example of classical probability, empirical probability, or subjective probability The probability that a newborn kitten is a male is .
classical
The ________________ measures the percentage of total variation in the response variable that is explained by the least squares regression line.
coefficient of determination
Computing the probability of the event "drawing a second red ball from a bag of colored balls after having kept the red ball that was drawn first from the bag" is an example of
conditional probability.
the cholesterol levels of a group of adults the day after Thanksgiving
continuous
the number of bottles of juice sold in a cafeteria during lunch
discrete
the number of pills in an aspirin bottle
discrete
Classify the statement as an example of classical probability, empirical probability, or subjective probability. It is known that the probability of hitting a pothole while driving on a certain road is 1%.
empirical probability
1. True or False: The probability that event A will occur is p(a) = numberofsuccessfuloutcomes/ numberofUnsuccessfuloutcomes
false
True or False: Type I and Type II errors are independent events.
false
Compare a graph of the normal density function with mean of 0 and standard deviation of 1 with a graph of a normal density function with mean equal to 0 and standard deviation of 0.5. The graphs would
have no horizontal displacement but one would be steeper than the other
the day of the month
interval
Cluster Sample
is obtained by selecting all individuals within a randomly selected collection or groups of individuals.
Systematic Sample
is obtained by selecting every "kth" individual from the population.The first individual selected corresponds to a random number between 1 and k. DOES NOT REQUIRE A FRAME, so it is useful for when you cannot obtain a list of individuals in the population.
Stratified Sample
is obtained by separating the population into non overlapping groups called strata and then obtaining a simple random sample from each stratum(Divisinions
The normal density curve is symmetric about
its mean
Find the class limits for the second class.
lower limit: 5.9; upper limit: 6.7
1The annual profits of five large corporations in a certain area are given below. Which measure of central tendency should be used? $209,000 $217,000 $237,000 $207,000 $1,287,000
median (used for extreme values)
The least squares regression line
minimizes the sum of the residuals squared.
a student's favorite sport
nominal
the medal received (gold, silver, bronze) by an Olympic gymnast
ordinal
The average age of the 65 students in Ms. Hope's political science class is 21 years 6 months
parameter
Parking at a large university has become a very big problem. University administrators are interested in determining the average parking time (e.g. the time it takes a students to find a parking spot) of its students. An administrator inconspicuously followed 210 students and carefully recorded their parking times. Identify the sample of interest to the university administration.
parking times of the 210 students
Telephone interviews of 318 employees of a large electronics company found that 45% were dissatisfied with their working conditions.
statistic
Classify the statement as an example of classical probability, empirical probability, or subjective probability. The probability that cab fares will rise during the winter is 0.05.
subjective probability
Find the area under the standard normal curve between z = 1 and z = 2.
subtract 1-2 from table - 0.1359
Describe the shape of the histogram. The data set: age of 20 household stereo systems randomly selected from a neighborhood 12 6 4 9 11 1 7 8 9 8 9 13 5 15 7 6 8 8 2 1
symmetric
Define confounding. Choose the correct answer below.
the effect of two factors (explanatory variables on the response variable) cannot be distinguished.
If the coefficient of determination is close to 1, then
the least squares regression line equation explains most of the variation in the response variable
A residual is the difference between
the observed value of y and the predicted value of x.
True or False: In a probability distribution, any random variable is just as likely as any other random variable to occur, provided the random variables belong to the distribution.
true
True or False: The probability of an event E in an empirical experiment may change from experiment to experiment.
true
True or False: The proportion of the population that has certain characteristics is the same as the probability that a randomly selected individual of the population has these same characteristics.
true
A contingency table relates
two categories of data
The data below are the number of absences and the final grades of 9 randomly selected students from a literature class. Find the equation of the regression line for the given data. What would be the predicted final grade if a student was absent 14 times? Round the regression line values to the nearest hundredth. Round the predicted grade to the nearest whole number.
y ̂=-2.75x+96.14;58
