Question 1

Describe why performing linear regression with these data is not a good decision.

Accepted Answer

The data is clearly curved, so using a l

Question 2

Comment on any unusual data point or points in the data set. Explain.

Accepted Answer

The points in the bottom left corner see

Question 3

Survey. A local news station wants to know what percentage of people favor investing in
new public light-rail system for the city. They conduct a survey, calling homes between
10:00 a.m. and 3:00 p.m. Explain why this sampling plan is biased.

Accepted Answer

Undercoverage bias: Calling people at ho

Question 4

Do you think the breed selection is independent of gender? Give statistical evidence to
support your conclusion.

Accepted Answer

The breed selection does not appear to b

Question 5

School administrators collect data on students attending the school. Which of the following
Variables is quantitative?

Accepted Answer

A)  grade point average 
B)  class (freshman, soph., junior, senior) 
C)  whether the student is in AP* classes 
D)  none of these 
E)  whether the student has taken the SAT 
A)  grade point average 
B)  class (freshman, soph., junior, senior) 
C)  whether the student is in AP* classes 
D)  none of these 
E)  whether the student has taken the SAT

Question 6

A friend of yours plans to toss a fair coin 200 times. You watch the first 40 tosses, noticing that she
Got only 16 heads. But then you get bored and leave. If the coin is fair, how many heads do you
Expect her to have when she has finished the 200 tosses?

Accepted Answer

A)  100 
B)  116 
C)  80 
D)  96 
E)  92 
A)  100 
B)  116 
C)  80 
D)  96 
E)  92

Question 7

The five-number summary of credit hours for 24 students in a statistics class is: $$\begin{array} { | c | c | c | c | c | } 
\hline \text { Min } & \text { Q1 } & \text { Median } & \text { Q3 } & \text { Max } \
\hline 13.0 & 15.0 & 16.5 & 18.0 & 22.0 \
\hline
\end{array}$$ Which statement is true?

Accepted Answer

A)  There is at least one low outlier in the data. 
B)  There is at least one high outlier in the data. 
C)  There are both low and high outliers in the data. 
D)  There are no outliers in the data. 
E)  none of these 
A)  There is at least one low outlier in the data. 
B)  There is at least one high outlier in the data. 
C)  There are both low and high outliers in the data. 
D)  There are no outliers in the data. 
E)  none of these

Question 8

Write the owner's null and alternative hypotheses.

Accepted Answer

The null hypothesis is that percentage o

Question 9

Trainers need to estimate the level of fat in athletes to ensure good health. Initial tests were based
On a small sample but now the trainers double the sample size for a followup test. The main
Purpose of the larger sample is to…

Accepted Answer

A)  reduce confounding due to other variables. 
B)  decrease the variability in the population. 
C)  reduce response bias. 
D)  decrease the standard deviation of the sampling model. 
E)  reduce non-response bias. 
A)  reduce confounding due to other variables. 
B)  decrease the variability in the population. 
C)  reduce response bias. 
D)  decrease the standard deviation of the sampling model. 
E)  reduce non-response bias.

Question 10

Explain what your P-value means in this context.

Accepted Answer

If the proportion of female athletes has

Question 11

A professor runs a regression to see how students' exam scores (Y) are related to their homework
Grades ( $$\text { (X). The } R ^ { 2 } \text { of the regression is } 21 \% \text {. What does } R ^ { 2 } \text { tell us }$$
?

Accepted Answer

A)  21% of each student's exam grade will be determined by their homework grade. 
B)  Exam scores are not related to homework grades since 21% is greater than 5%. 
C)  none of these 
D)  21% of students have their grades accurately predicted by the regression equation. 
E)  21% of the variation in the exam scores is explained by the regression analysis. 
A)  21% of each student's exam grade will be determined by their homework grade. 
B)  Exam scores are not related to homework grades since 21% is greater than 5%. 
C)  none of these 
D)  21% of students have their grades accurately predicted by the regression equation. 
E)  21% of the variation in the exam scores is explained by the regression analysis.

Question 12

In this context describe a Type I error and the impact such an error would have on the
company.

Accepted Answer

A Type I error would be concluding the p

Question 13

Identify what is wrong with each of the following statements:
a. The correlation between Olympic gold medal times for the 800m hurdles and year is
-0.66 seconds per year.
b. The correlation between Olympic gold medal times for the 100m dash and year is -1.37.
c. Since the correlation between Olympic gold medal times for the 800m hurdles and 100m
dash is -0. 41, the correlation between times for the 100m dash and the 800m hurdles is
+0.41.
d. If we were to measure Olympic gold medal times for the 800m hurdles in minutes
instead of seconds, the correlation would be $- 0.66 / 60 = - 0.011$

Accepted Answer

a. Correlation has no units.
b

Question 14

Car commercials A car dealer investigated the association between the number of TV
commercials he ran each week and the number of cars he sold the following weekend. He
found the correlation to be r = 0.56. During the time he collected the data he ran an average
of 12.4 commercials a week with a standard deviation of 1.8, and sold an average of 30.5
cars with a standard deviation of 4.2. Next weekend he is planning a sale, hoping to sell 40
cars. Create a linear model to estimate the number of commercials he should run this week.
Write a sentence explaining your recommendation.

Accepted Answer

Explanatory variable @#LAT-DLM& : the number of ca

Question 15

Approval rating The President's job approval rating is always a hot topic. Your local paper
conducts a poll of 100 randomly selected adults to determine the President's job approval
rating. A CNN/USA Today/Gallup poll conducts a poll of 1010 randomly selected adults.
Which poll is more likely to report that the President's approval rating is below 50%,assuming that his actual approval rating is 54%? Explain.

Accepted Answer

The smaller poll would have more variabi

Question 16

A residual plot that has no pattern is a sign that…

Accepted Answer

A)  the original data is straight and the regression line is not a good model. 
B)  the original data is curved and the regression line is a good model. 
C)  the model is not a good one, because there is no pattern. 
D)  the original data is curved and the regression line is not a good model. 
E)  the original data is straight and the regression line is a good model. 
A)  the original data is straight and the regression line is not a good model. 
B)  the original data is curved and the regression line is a good model. 
C)  the model is not a good one, because there is no pattern. 
D)  the original data is curved and the regression line is not a good model. 
E)  the original data is straight and the regression line is a good model.

Question 17

If he gets only 5 nibbles on his line, is that a signal that he is having less success than usual?
Justify your answer.

Accepted Answer

@#LAT-DLM&
Three standard devi

Question 18

The Wechsler Adult Intelligence Scale - Revised (WAIS-R) follows a Normal model with
mean 100 and standard deviation 15. Draw and clearly label this model.

Accepted Answer

The answer of The Wechsler Adult Intelligence Scale - Revised...

Question 19

A school district administrator sent a survey to all teachers in the district. Only 30% of the teachers
Responded to the survey. Which of the following is true?
I. The people that did not responded are likely to be similar to those that did so he should use them
As the sample.
II. This survey design suffered from non-response bias.
III. Because he sent the survey to everyone, this is a census and the results can be applied to the
Whole population.

Accepted Answer

A)  II and III only 
B)  I only 
C)  II only 
D)  I, II, and III 
E)  I and II only 
A)  II and III only 
B)  I only 
C)  II only 
D)  I, II, and III 
E)  I and II only

Question 20

Which two events are most likely to be independent?

Accepted Answer

A)  having a car accident; having a junior license 
B)  doing the Statistics homework; getting an A on the test 
C)  having 3 inches of snow in the morning; being on time for school 
D)  being a senior; going to homeroom 
E)  registering to vote; being left-handed 
A)  having a car accident; having a junior license 
B)  doing the Statistics homework; getting an A on the test 
C)  having 3 inches of snow in the morning; being on time for school 
D)  being a senior; going to homeroom 
E)  registering to vote; being left-handed

Describe why performing linear regression with these data is not a good decision.

Comment on any unusual data point or points in the data set. Explain.

Survey. A local news station wants to know what percentage of people favor investing in new public light-rail system for the city. They conduct a survey, calling homes between 10:00 a.m. and 3:00 p.m. Explain why this sampling plan is biased.

Do you think the breed selection is independent of gender? Give statistical evidence to support your conclusion.

School administrators collect data on students attending the school. Which of the following Variables is quantitative?

A friend of yours plans to toss a fair coin 200 times. You watch the first 40 tosses, noticing that she Got only 16 heads. But then you get bored and leave. If the coin is fair, how many heads do you Expect her to have when she has finished the 200 tosses?

The five-number summary of credit hours for 24 students in a statistics class is: Min Q1 Median Q3 Max 13.0 15.0 16.5 18.0 22.0 Which statement is true?

Write the owner's null and alternative hypotheses.

Trainers need to estimate the level of fat in athletes to ensure good health. Initial tests were based On a small sample but now the trainers double the sample size for a followup test. The main Purpose of the larger sample is to…

Explain what your P-value means in this context.

A professor runs a regression to see how students' exam scores (Y) are related to their homework Grades ( $\text { (X). The } R ^ { 2 } \text { of the regression is } 21 \% \text {. What does } R ^ { 2 } \text { tell us }$ ?

In this context describe a Type I error and the impact such an error would have on the company.

A residual plot that has no pattern is a sign that…

If he gets only 5 nibbles on his line, is that a signal that he is having less success than usual? Justify your answer.

The Wechsler Adult Intelligence Scale - Revised (WAIS-R) follows a Normal model with mean 100 and standard deviation 15. Draw and clearly label this model.

Which two events are most likely to be independent?

Exploring and Understanding Data

Exploring Relationships Between Variables

Gathering Data

Randomness and Probability

From the Data at Hand to the World at Large

Accessing Associations Between Variables

Inference When Variables Are Related

Filters

Exam 8: Regression, Associations, and Predictive Modeling

Describe why performing linear regression with these data is not a good decision.

Comment on any unusual data point or points in the data set. Explain.

Survey. A local news station wants to know what percentage of people favor investing in new public light-rail system for the city. They conduct a survey, calling homes between 10:00 a.m. and 3:00 p.m. Explain why this sampling plan is biased.

Do you think the breed selection is independent of gender? Give statistical evidence to support your conclusion.

School administrators collect data on students attending the school. Which of the following Variables is quantitative?

A friend of yours plans to toss a fair coin 200 times. You watch the first 40 tosses, noticing that she Got only 16 heads. But then you get bored and leave. If the coin is fair, how many heads do you Expect her to have when she has finished the 200 tosses?

The five-number summary of credit hours for 24 students in a statistics class is: Min Q1 Median Q3 Max 13.0 15.0 16.5 18.0 22.0 Which statement is true?

Write the owner's null and alternative hypotheses.

Trainers need to estimate the level of fat in athletes to ensure good health. Initial tests were based On a small sample but now the trainers double the sample size for a followup test. The main Purpose of the larger sample is to…

Explain what your P-value means in this context.

In this context describe a Type I error and the impact such an error would have on the company.

A residual plot that has no pattern is a sign that…

If he gets only 5 nibbles on his line, is that a signal that he is having less success than usual? Justify your answer.

The Wechsler Adult Intelligence Scale - Revised (WAIS-R) follows a Normal model with mean 100 and standard deviation 15. Draw and clearly label this model.

Which two events are most likely to be independent?

Exploring and Understanding Data

Exploring Relationships Between Variables

Gathering Data

Randomness and Probability

From the Data at Hand to the World at Large

Accessing Associations Between Variables

Inference When Variables Are Related

Filters