yas
A Lake Tahoe Community College instructor is interested in the average number of days Lake Tahoe Community College math students are absent from class during a quarter that lasts 9 weeks. The instructor takes her sample by gathering data on the first 25 students that enroll in a Lake Tahoe Community College math class. Which of the following best describes the type of sample that was taken?
Convience sample
18 18 19 21 21 21 21 21 22 22 24 24 25 26 28 29 30 30 31 31 31 35 35 36 40 What is the 5-number Summary for this data?
Min = 18; Q1 = 21; Median = 25; Q3 = 31; Maximum = 40
Data: 6.8, 7.1, 6.3, 7.4, 5.1, 4.3, 4.7, 4.5, 4.9, 5.8, 4.3, 6.3 4.7, 3.6, 7.6, 6.7, 2.8, 4.7, 7.2, 3.6, 5.3, 3.6, 5.6, 4.6 What is the 5-number summary for this data?
Min = 2.8; Q1 = 4.4; Median = 5; Q3 = 6.5; Maximum = 7.6
Suppose the average annual amount of rainfall in San Diego is 10.34 inches with a standard deviation of 1.7 inches. Assuming the Empirical Rule is appropriate the amount of annual rainfall falls within what interval 95% of the time?
(6.94,13,74)
Year Time (seconds) 1995 58.68 1996 58.29 1997 57.79 1998 56.90 2000 56.56 2002 56.34 2006 55.95 2008 55.74 2009 55.05 Using x = 5 to represent the year "1995," what is the slope of the LSRL for the data?
-0.2168
Suppose a set of data follows the distribution N(35, 5.8). What is the z-score for a value of 32?
-0.52
The least squares regression line describing race times (in minutes) on number of days since the track season started is . racetimes (hat) = 2.58-0.012(days) The race times have a mean of 2.28 and a standard deviation of 0.096. The number of days since the season started has a mean of 25 and a standard deviation of 6.4. What is the value of the correlation between the number of days the season started and the race times?
-0.8
According to Washit, the average cost for a 50oz container of laundry detergent is $14.24. Assuming a standard deviation of $2.52, what is the z-score for a leading brand of laundry detergent that costs $11.97 for a 50oz container?
-0.9
Suppose the time it takes drivers to wait for a red light to change to a green light is uniformly distributed between 0 and 20 seconds. What proportion of drivers have a wait time that is greater than 15 seconds?
.25
The Sky Train from the terminal to the rental car and long term parking center is supposed to arrive every 8 minutes. The waiting times for the train are known to follow a uniform distribution. What is proportion of people wait more than 7 minutes given that they have waited more than 4 minutes?
.25
On average, a garbage company dumps 2.43 kilotons of garbage into a landfill each day. Assuming a normal distribution with a standard deviation of 0.88 kilotons, what is the probability that the company will dump more than 3 kilotons into the landfill in a day?
.2611
Given the uniform distribution: X ~ U(0,30), what proportion of values are greater than 15?
.5
The Sky Train from the terminal to the rental car and long term parking center is supposed to arrive every 8 minutes. The waiting times for the train are known to follow a uniform distribution. What proportion of people wait less than 2 minutes or more than 6 minutes?
.5
Suppose that the average wait time at the local coffee shop from the time you order to the time you receive your drink is normally distributed with a mean of 3.5 minutes and a standard deviation of 1.2 minutes. What proportion of people will wait between 3 and 5 minutes?
.5572
The table represents data from a random sample of 100 clients. X Frequency 0 3 1 12 2 33 3 28 4 11 5 9 6 4 What value is 1.5 standard deviations below the mean?
.701
Data: 6.8, 7.1, 6.3, 7.4, 5.1, 4.3, 4.7, 4.5, 4.9, 5.8, 4.3, 6.3 4.7, 3.6, 7.6, 6.7, 2.8, 4.7, 7.2, 3.6, 5.3, 3.6, 5.6, 4.6 How many outliers are in this data set?
0
Suppose that the heights of 4-year old boys are normally distributed with a mean of 103cm and a standard deviation of 4.05cm. What is the probability a randomly chosen 4-year old is shorter than 91.4cm (3 feet)?
0.0021
Suppose that the average wait time at the local coffee shop from the time you order to the time you receive your drink is normally distributed with a mean of 3.5 minutes and a standard deviation of 1.2 minutes. About what percent of the time will a person wait for over 5 minutes?
10.56%
Suppose that the heights of 4-year old boys are normally distributed with a mean of 103cm and a standard deviation of 4.05cm. Half of all 4-year olds are shorter than:
103cm
Suppose that the heights of 4-year old boys are normally distributed with a mean of 103cm and a standard deviation of 4.05cm. What height represents the 95th percentile?
109.66 cm
Given the uniform distribution: X ~ U(0,30), what is the median of X?
15
18 18 19 21 21 21 21 21 22 22 24 24 25 26 28 29 30 30 31 31 31 35 35 36 40 The middle 50% of the data lie between what two values?
18 and 26.36
Suppose the time it takes drivers to wait for a red light to change to a green light is uniformly distributed between 0 and 20 seconds. Ninety percent of the time a driver's wait time falls below what value?
18 seconds
The Sky Train from the terminal to the rental car and long term parking center is supposed to arrive every 8 minutes. The waiting times for the train are known to follow a uniform distribution. Find the 30th percentile for the waiting times (in minutes).
2.4
Suppose that the heights of 4-year old boys are normally distributed with a mean of 103cm and a standard deviation of 4.05cm. About what percent of 4-year olds are taller than 111.1cm?
2.5%
The table represents data from a random sample of 100 clients. X Frequency 0 3 1 12 2 33 3 28 4 11 5 9 6 4 What is the mean number of days per week a client uses this particular exercise facility?
2.75
If a the middle 99.7% of test scores are between 50 and 70, what is the estimate of the standard deviation of the scores, assuming they are normally distributed?
3.33
An experiment compared the durability of 2 types of paint, R and S, to 3 types of plastic, 1, 2, and 3, used on elementary school chairs. Thirty chairs were used in the experiment: 10 of plastic 1, 10 of plastic 2, and 10 of plastic 3. Half of each plastic type will receive paint R and the other half will receive paint S. The durability of the paints was measured, and the measures were compared. How many experimental units are in the experiment?
30
A Lake Tahoe Community College instructor is interested in the average number of days Lake Tahoe Community College math students are absent from class during a quarter that lasts 9 weeks. What is the population she is interested in?
All Lake Tahoe Community College math students
A group of 100 mothers were asked to choose their favorite TV genre from the following choices: Reality TV, Comedy, Drama or Sports. Which of the following visual displays is most appropriate for the resulting data?
Bar Graph
Suppose that the average wait time at the local coffee shop from the time you order to the time you receive your drink is normally distributed with a mean of 3.5 minutes and a standard deviation of 1.2 minutes. Which of the following is the smallest interval that contains about 10% of the data?
Between 3.349 and 3.651 minutes
A flight attendant wonders if they how he offers passengers a snack affects what snack they choose. The airline offers peanuts and pretzels. Per past experience, he knows that snack choice is highly affected by gender. On the flight of 64 passengers, he notates all of the females' seat numbers and all of the males' seat numbers. Then he randomly splits the female group in half...where the first half will be asked, "Do you want peanuts or pretzels?" and the second half will be asked "Do you want pretzels or peanuts?" He does the same procedure for the males. During the flight he takes note of everyone's choice and then measures and compares the number of each snack item chosen. What type of experimental design did the flight attendant use?
Block Design
A company manager for a tire manufacturer is in charge of making sure there is the least amount of defective tires. If the tire manufacturing process is working properly, the average weight of a tire for a 4-door sedan is normally distributed with a mean of 22 pounds and a standard deviation of 0.76 pounds. The manager decides to reject a tire as underweight if it falls more than 1.5 interquartile ranges below the lower quartile of the specified shipment of tires. What proportion of tires will be rejected by this process?
0.0035
Quality control plan #2 calls for rejecting a set of headphones as "defective" if its amount of noise cancelation falls more than 1.5 interquartile ranges below the lower quartile of the specified population. What proportion of headphones will be rejected by plan #2?
0.0035
Quality control plan #1 calls for rejecting a set of headphones as "defective" if its amount of noise cancelation falls more than 2 standard deviations below the specified mean What proportion of headphones will be rejected by plan #1?
0.025
Given the uniform distribution: X ~ U(0,30), what proportion of values are less than 30?
1
Two teachers, Mrs. Smith and Mr. Keeping, gave the same quiz to two different classes. Mr. Keeping asked Mrs. Smith if she had any students whose score was an outlier. She could remember the following information without looking at all her quizzes: Her top three scores were 35, 48 and 50. Her lowest three scores were 11, 17 and 18. Her Q1 was 22 and her Q3 was 33 How many outliers did Mrs. Smith have?
1
Which of the following are true? - The area under a normal curve is always 1 regardless of the mean and standard deviation - The mean is always equal to the median for any normal distribution - Increasing the frequency of the tails in a normal distribution will decrease the standard deviation
1 and 3
The following data are the results of a random survey of 110 army reserve personnel called to active duty in the aftermath of an earthquake disaster. Dependents. Freq 0, 11 1, 27 2, 33 3, 20 4, 19 What is the cumulative relative frequency of reserve personnel with 4 or fewer dependents?What is the cumulative relative frequency of reserve personnel with 4 or fewer dependents?
1.0
Suppose that the average wait time at the local coffee shop from the time you order to the time you receive your drink is normally distributed with a mean of 3.5 minutes and a standard deviation of 1.2 minutes. According to the Empirical Rule, 95% of the time a person needs to wait between what two values?
1.1 and 5.9 minutes
In a teacher's math course, a linear regression line was calculated to predict a student's final exam score from the score he received on the midterm. The equation was y(hat) = 25.5 + 0.8x where y is the final exam score and x is the score on the midterm. AJ scored 90 on the midterm. AJ actually scored 99 on his final exam. What is the value of his residual?
1.5
Given the uniform distribution: X ~ U(0,30), what proportion of values are between 10 and 20?
1/3
Which of the following statistics are resistant? Mean and Standard Deviation Mean and Median Median and IQR Mean and IQR None of these statistics are resistant
Median, IQR
The Sky Train from the terminal to the rental car and long term parking center is supposed to arrive every 8 minutes. The waiting times for the train are known to follow a uniform distribution. What is the average waiting time (in minutes)?
4.0
She gathers some data from her friends' families and calculates the following least squares regression line: y(hat) = 3.45+4.15x where y = the number of dishes to wash and x = the number of side dishes made. How many extra dishes should Scottie expect to wash, on average, for each additional side dish her family makes?
4.15
Suppose that the average wait time at the local coffee shop from the time you order to the time you receive your drink is normally distributed with a mean of 3.5 minutes and a standard deviation of 1.2 minutes. What wait time represents the 85th percentile?
4.748
She gathers some data from her friends' families and calculates the following least squares regression line: y(hat) = 3.45+4.15x where y = the number of dishes to wash and x = the number of side dishes made. If Scottie's family is planning on making 12 side dishes, how many dishes is she predicted to wash?
58.25
Year Time (seconds) 1995 58.68 1996 58.29 1997 57.79 1998 56.90 2000 56.56 2002 56.34 2006 55.95 2008 55.74 2009 55.05 Using x = 5 to represent the year "1995," what is the y-intercept of the LSRL for the data above?
59.24
Suppose a group of high school students are measured for a school data collection project. If a the middle 95% of students were between 5 feet and 7 feet tall , what is the estimate of the standard deviation of the scores, assuming they are normally distributed?
6 inch
A student finds that the coefficient of determination between age and IQ is 0.60. What percentage of variation in IQ can be explained by the linear relationship with age?
60%
A student finds that the correlation coefficient between shoe size and height is 0.78. What percentage of variation in height can be explained by the linear relationship with show size?
60.87%
Year Time (seconds) 1912 82.2 1924 72.4 1932 66.8 1952 66.8 1960 61.2 1968 60.0 1976 55.65 1984 55.92 1992 54.64 Using x = 12 to represent the year "1912," what is the slope of the LSRL?
81.346
Year Time (seconds) 1912 82.2 1924 72.4 1932 66.8 1952 66.8 1960 61.2 1968 60.0 1976 55.65 1984 55.92 1992 54.64 Using x = 12 to represent the year "1912," what is the y-intercept of the LSRL?
81.346
In a teacher's math course, a linear regression line was calculated to predict a student's final exam score from the score he received on the midterm. The equation was y(hat) = 25.5 + 0.8x where y is the final exam score and x is the score on the midterm. AJ scored 90 on the midterm. What is the predicted value of his score on the final exam?
97.5
A personal trainer knows that a person's weight is usually affected by diet and exercise. He has a shorter but more intense training regimen that he thinks would increase weight loss in his clients more so than the longer less intense routine. He has 20 clients that agree to be a part of his experiment. Explain why a randomized block design would be a better choice than a completely randomized design in this situation.
A randomized block design would account for individual differences. Each client will have individual differences in metabolism, fitness level, diet, lifestyle etc. These factors could influence results, and can introduce lots of variability in results. This also lets us control confounding variables, which in turn increases the precision. Blocking by certain factors like mentioned above can get us more precise estimates of the effects of training regiments on weight loss. In a random design all 20 clients would simply be randomly assigned to one of two training regimens without considering their individual characteristics! This could lead to imbalances where by chance one group might have more clients with faster metabolisms and better fitness levels. With this the trainer can ensure these individual differences are balanced across two treatment levels.
A Lake Tahoe Community College instructor is interested in the average number of days Lake Tahoe Community College math students are absent from class during a quarter that lasts 9 weeks. The instructor takes her sample by gathering data on 25 randomly selected students from all students enrolled in a Lake Tahoe Community College math class. Which of the following best describes the type of sample that was taken?
A simple random sample
A Lake Tahoe Community College instructor is interested in the average number of days Lake Tahoe Community College math students are absent from class during a quarter that lasts 9 weeks. The instructor takes her sample by gathering data on 5 randomly selected students from each Lake Tahoe Community College math class. Which of the following best describes the type of sample that was taken?
A stratified random sample
A mom decided to bake cookies for her daughter's class 4th grade class each month. The teacher (who has an interest in statistics) collected data on how many minutes passed (x) versus how many cookies were left on the plate (y). When she performed a least squares regression, she obtained r = -0.87. Interpret the coefficient of determination (r^2).
About 75.69% of the variation in cookies left on the plate can be explained by the Least Square Regression of cookies left on the plate on hoe many minutes passed.
A store decides to take off 20% off all merchandise for customer appreciation day. Suppose that before customer appreciation the mean price of an item at this store day was $35.60 with a standard deviation of $9.80. What will the mean and standard deviation of item prices be on customer appreciation day?
Mean = $28.48; Standard Deviation = $7.84
Breshleim wanted to demonstrate which fertilizer was best for the growth of certain types of flower plant. She selected 20 flower plants of the same type and randomly assigned each one to receive one of twenty different fertilizers. Three weeks after adding the fertilizer, she measured the regrowth, in inches, of the flower plants; the fertilizer that maximized regrowth was recommended as the best method. Which of the following best describes why this is not a well-designed experiment?
Each fertilizer was only used on one flower plant
18 18 19 21 21 21 21 21 22 22 24 24 25 26 28 29 30 30 31 31 31 35 35 36 40 Which of the following best describes the shape of this distribution of US Olympic Snowboarding Team ages in 2022? Uniform Fairly Symmetric...slightly skewed left Two clusters with a gap in the middle Fairly Symmetric...slightly skewed right Perfectly bell shaped
Fairly Symmetric...slightly skewed right
A student is gathering data about the number of minutes it takes his classmates to get to school in the morning. He gets data from 500 students at his high school. Which of the following visual displays is most appropriate?
Histogram
Which of the following statistics is a resistant measure? Mean Standard Deviation Range Variance IQR
IQR
Suppose the correlation between two variables is -0.73. If each of the y-values are multiplied by -1, which of the following is true about the new scatterplot?
It slopes up to the right and the correlation is +0.73
A principal would like to use a random number table to select simple random sample of 100 students from his high school. There are 500 students in each grade level (9th , 10th, 11th and 12th) and 9 different buildings on campus. Which of the following labeling methods would be the best option for his sampling?
Label each student in the school with a number from 0001 to 2000
According to Education.com, in 2002, there were 23 states in which more than 50% of high school graduates took the SAT. The following computer output gives the regression analysis for predicting SAT Math scores from SAT Verbal scores for these 23 states. Coef StDev t P Coef 185.77 71.45 2.60 0.017 Verbal 0.6410 0.1420. 4.52 0.000 s=7.457 R-sq = 49.3% R-sq(adj)=46.9% What is the LSRL for this output?
Math (hat) = 185.77 + 0.6419 (Verbal)
Which of the following is not needed to construct a boxplot?
Mean
Here is a list of home prices in a certain region: $229,000 $250,000 $260,000 $271,000 $285,000 What is the mean and standard deviation of this sample of home prices?
Mean = $259,000; Standard Deviation = $21,225
Suppose the mean cost of a coffee drink at a local coffee establishment is $4.35 with a standard deviation of $0.83. If the manager decides to lower every drink price by 25 cents, what will be the new mean and standard deviation of the distribution of new prices?
Mean = $4.10; Standard deviation = $0.83
Which of the following is resistant (not affected by outliers)? Slope LSRL Correlation coefficient Coefficient of determination None of these are resistant measures
None
A mom decided to bake cookies for her daughter's 4th grade class each month. The teacher (who has an interest in statistics) collected data on how many minutes passed versus how many cookies were left on the plate. Her LSRL for the cookie data was: hat(Cookies) = 36.24 - 0.631(Time) Interpret the slope of this LSRL.
On average, when the time passes in minutes increases by 1, the predicted cookies left on the plate decrease by about 0.631.
A group of 50 students were asked about their favorite color. Here are the results: Red: 15 Blue: 11 Purple: 7 Yellow: 8 Pink: 6 Green: 3 Which of the following visual displays is most appropriate for this data? Boxplot Histogram Stemplot Dotplot Pie Chart
Pie Chart
A mom decided to bake cookies for her daughter's class 4th grade class each month. The teacher (who has an interest in statistics) collected data on how many minutes passed (x) versus how many cookies were left on the plate (y). When she performed a least squares regression, she obtained r = -0.87. Interpret the correlation coefficient.
Since r=-0.87 is close to -1, there is a strong, negative, linear relationship between minutes passed & how many cookies were left on the plate.
If the mean of a distribution is less than the median, the distribution is most likely
Skewed Left
A marketing company is interested in obtaining a sample of teenagers to view a trailer for a new movie to give their opinion on whether or not the trailer convinces them to see the full movie. They want to make sure that they get the opinions of both males and females. The company divides the population into two groups (males and females) and then takes a random sample of 60 teenagers from each group. This is an example of what type of sample?
Stratified random sample
Which of the following statements is the only sentence that is error-free? There is a correlation of 1.23 between the hours of study and test scores. The correlation between vegetable type and amount of water needed is 0.54. The correlation between a husband's weight and his wife's weight is r = 0.76 pounds. There is a correlation of r = 1 between favorite restaurant and distance the restaurant is from home. The correlation between hours of practice and a golfer's average score is found to be -0.82.
The correlation between hours of practice and a golfer's average score is found to be -0.82.
Which of the following statements is correct? - There is a correlation of 0.76 between the position a soccer player plays and his speed. - The correlation between planting rate and amount of strawberries grown is 0.54. - The correlation between arm span and height is r = 0.98 inches - The correlation between a child's age and his weight is found to be 1.09 - There is a correlation of r = -0.44 between gender and favorite color.
The correlation between planting rate and amount of strawberries grown is 0.54.
What does the coefficient of determination measure?
The percentage of variation in the y-variable that is explained by the LSRL of y on x.
What does correlation measure?
The strength and direction of the linear relationship between two quantitative variables
A flight attendant wonders if they how he offers passengers a snack affects what snack they choose. The airline offers peanuts and pretzels. Per past experience, he knows that snack choice is highly affected by gender. On the flight of 64 passengers, he notates all of the females' seat numbers and all of the males' seat numbers. Then he randomly splits the female group in half...where the first half will be asked, "Do you want peanuts or pretzels?" and the second half will be asked "Do you want pretzels or peanuts?" He does the same procedure for the males. During the flight he takes note of everyone's choice and then measures and compares the number of each snack item chosen. Which of the following is NOT true? The 64 passengers are subjects in an experiment There are two treatments imposed in this experiment Gender is a blocking variable in this experiment There are two explanatory variables
There are two explanatory variables in this experiment, gender and how he asks the question
Which of the following statements is true about histograms? Histograms are used to graph categorical variables Two students that are graphing the same data set can have different looking histograms Histograms are used more often than dotplots because histograms display the values of individual observations The x-axis of a histogram is always scaled in percentages or proportions If a large data set contains numbers that are all the same, the histogram will be skewed right
Two students that are graphing the same data set can have different looking histograms
In response to nutrition concerns raised last year about food served in school cafeterias, the Smallville School District entered into a one-year contract with the Healthy Alternative Meals (HAM) company. Under this contract, the company plans and prepares meals for 2,500 elementary, middle, and high school students, with a focus on good nutrition. The school administration would like to survey the students in the district to estimate the proportion of students who are satisfied with the food under this contract. Two sampling plans for selecting the students to be surveyed are under consideration by the administration. One plan is to take a simple random sample of students in the district and then survey those students. The other plan is to take a stratified random sample of students in the district and then survey those students. Describe a simple random sampling procedure that the administrators could use to selec
a. 1. Assign a unique number (within a range of 0001-2500) to each of the 2500 students in the district. 2. Use a random number generator or random table to select 200 numbers from the range 0001 to 2500. Ensuring each student has an equal chance of being chosen, for said sample. Once 200 numbers are chosen, stop. 3. Identify, the students correspond with the randomly generated numbers, as these students were chosen for this survey.
Suppose that the heights of 4-year old boys are normally distributed with a mean of 103cm and a standard deviation of 4.05cm. Which of the following is the smallest interval that contains 20% of the data?
add awns
A principal at a local high school wants to know what his students think about a proposed "off-campus lunch" rule. He takes a random sample of students and finds that 78 out of the 123 sampled students are in favor of the proposed rule. What is the population in this situation?
all students at the local high school
In response to nutrition concerns raised last year about food served in school cafeterias, the Smallville School District entered into a one-year contract with the Healthy Alternative Meals (HAM) company. Under this contract, the company plans and prepares meals for 2,500 elementary, middle, and high school students, with a focus on good nutrition. The school administration would like to survey the students in the district to estimate the proportion of students who are satisfied with the food under this contract. Two sampling plans for selecting the students to be surveyed are under consideration by the administration. One plan is to take a simple random sample of students in the district and then survey those students. The other plan is to take a stratified random sample of students in the district and then survey those students. If a stratified random sampling procedure is used, give one example of an effective va
b. One effective variable could be Grade Level, given that High School students may respond differently, to elementary school students. An example of this is that younger students might be less picky about non-healthy options, compared to their High School counterparts. Below is how they could conduct a stratified random sample... 1. Divide students into three strata, elementary, middle and high school students... 2. Within each stratum, use SRS to randomly select the appropriate number of students for this survey. As this number will be reflective of how many students are in each strata.
In response to nutrition concerns raised last year about food served in school cafeterias, the Smallville School District entered into a one-year contract with the Healthy Alternative Meals (HAM) company. Under this contract, the company plans and prepares meals for 2,500 elementary, middle, and high school students, with a focus on good nutrition. The school administration would like to survey the students in the district to estimate the proportion of students who are satisfied with the food under this contract. Two sampling plans for selecting the students to be surveyed are under consideration by the administration. One plan is to take a simple random sample of students in the district and then survey those students. The other plan is to take a stratified random sample of students in the district and then survey those students. Describe one statistical advantage of using a stratified random sample over a simple r
c. One advantage of using a SRS over a simple random sample in this context, is that is allow more precise estimates of satisfaction within grade level. By stratifying each, you're ensuring that each group gets the representation according to their subgroup size. This approach is much more nuanced, compared to a random survey, that could potentially only choose one demographic of Students at Smallville School District.
A researcher wanted to know the average salary for teachers in his state. He randomly selected 30 schools in his state and got the salary information from every teacher from each school. Which of the following best represent the type of sample that was taken?
cluster sample
A student wanted to determine the average number of books that high school teachers have in their office. The student randomly selected 2 buildings on campus and asked each teacher in the selected buildings how many books are in his/her office. The student surveyed 25 professors. The type of sampling selected is a:
cluster sample
To investigate the effectiveness of an herbal medication for lowering blood pressure, a researcher randomly selected 80 patients who were diagnosed with high blood pressure. Of the patients, 40 were over sixty years old, 16 were between forty and fifty years old, and 24 were under forty years old. The researcher will use two treatments for the investigation: the herbal medication and a standard medication. After the patients are on the medication for two weeks, the amount of blood pressure reduction will be measured for each patient. Which of the following best describes why a randomized block design is appropriate for the investigation?
locking on age will help to separate natural variability from differences due to age
Which of the following is resistant? Correlation coefficient LSRL Slope Coefficient of determination None of these are resistant measures
none
500 San Diegans were randomly selected to answer survey questions about their feelings about a downtown stadium. Each of the 500 people that were selected was emailed a link to the survey. 220 of the 500 people completed the survey. Which of the following bias is present in this sampling design?
nonreponse
Which of the following is the entire collection of persons, things, or objects in a statistical study?
population
What is a portion or subset of a larger population known as?
sample
If the mean is larger than the median in a distribution, the distribution is most likely
skewed right
In a distribution of cooking times for a sample of cakes, the mean cooking time is 54.2 minutes while the median cooking time is 41.8 minutes. The distribution of these cakes' cooking times is most likely
skewed right
A density curve is described by a straight line segment starting at the origin with a slope of 1. What is the right-endpoint of the line segment to make this a valid density curve?
sqrt(2), sqrt(2)
Which words below make the following sentence true? In a normal distribution, the z-score gives how many ____________ that the value x is above (to the right of) or below (to the left of) the ____________.
standard deviations, mean
The graph of a normal distribution is
symmetric
A pre-school teacher has a set of data describing her students' number of minutes of nap time and the number of tantrums in the afternoon. She has a feeling that the amount of sleep a toddler gets can contribute to whether or not they have a tantrum-free afternoon...in fact, she found that the correlation between these variables is -0.68. The mean amount of sleep her pre-schoolers got has a mean of 92.1 minutes with a standard deviation of 8.5 and the mean number of tantrums in the afternoon is 2.4 with a standard deviation of 0.54. With this information, what is the equation of the LSRL for number of tantrums on minutes of naptime?
tantrums(hat) = 6.38 - 0.0432(minutes)
Suppose two populations X and Y with normal distributions have the same means, but Y has a standard deviation twice that of X. How does the percentage of observations falling within two standard deviations of the mean compare between the two populations?
the percentage is the same for both
