Title: Default for Exploring Data
Course: Statistics: Exploring Data (9th-12th)

Q: Read the statistical claim below, and then provide at least two reasons why the claim needs to be interpreted with caution.

8 out of 10 doctors recommend our pain reliever.
A: Some examples:
Feedback ("Some examples:"): 1. No information is given about the nature of the survey questions. Perhaps the doctors consider the pain reliever to be just as effective as another, but it was less expensive. 2. No information is given about how the survey participants were selected. The doctors surveyed may not have been randomly selected. They may have been chosen from a group of doctors known to recommend one brand over another. 3. No information is given about how the results were analyzed. Perhaps 100 doctors were surveyed and somewhere in the group of 100 doctors there was a streak where 8 out of 10 of doctors recommended brand X.

Q: Read the statistical claim below, and then provide at least two reasons why the claim needs to be interpreted with caution.

Traffic accidents are reduced by 20 % when people use our brakes.
A: Some examples:
Feedback ("Some examples:"): 1. Consider variable that are not included in the statement. a) Is the 20% reduction between those cars that had their breaks fixed and those cars that did not have their breaks fixed? b) Perhaps there are other brakes that reduce accidents by an even greater amount. 2. The claim does not include information about how the drivers of the cars. Were the drivers of the cars the same before and after the brakes were changed? 3. The claim does not include information about how the cars were selected. Were the cars randomly selected? Were the cars selected from a group of cars known to respond in a particular way to these brakes?

Q: Read the statistical claim below, and then provide at least two reasons why the claim needs to be interpreted with caution.

In our radio survey, 75 % of respondents prefer Rock and Roll Johnny over Freddie Folk Song.
A: Some answers:
Feedback ("Some answers:"): 1. There is a built in bias because it was a radio show. The listener has a preference that will be reflected in a survey about musicians. 2. We do not know if the question was asked without bias. The question could have been: "Do you prefer the modern rhythms of Johnny or do you prefer the traditional sounds of Freddie?" The question associates 'modern' and 'traditional' with the music.

Q: The questions from the survey are copied below:
1. What is your favorite color?
2. How many pairs of shoes do you own?
3. On which day of the month were you born?

Which of the questions involves a categorical variable?
- Questions 1 and 2
- Questions 1 and 3
- Questions 2 and 3.
A: Questions 1 and 3

Q: The questions from the survey are copied below:
1. What is your favorite color?
2. How many pairs of shoes do you own?
3. On which day of the month were you born?

Which of the questions involves a quantitative variable?
- Question 1 only.
- Question 2 only.
- Question 3 only.
- Question 1 and 2.
- Questions 1 and 3.
A: Question 2 only.

Q: The questions from the survey are copied below:
1. What is your favorite color?
2. How many pairs of shoes do you own?
3. On which day of the month were you born?

Name the individual for Question 3.
A: You - the student.
Feedback ("You - the student."): Correct. The student is the individual that is being measured.

Q: The questions from the survey are copied below:
1. What is your favorite color?
2. How many pairs of shoes do you own?
3. On which day of the month were you born?

Name the variable being measured in question 1.
A: favorite color
Feedback ("favorite color"): Correct. The individual is the student, and the characteristic or variable being measured about that student is favorite color.

Q: For the situation described
a) describe the variable
b) tell if the variable is categorical or quantitative
c) if the variable is quantitative, then describe it further as either continuous or discrete.

A quality control worker with Sweet-tooth Candy weighs every [Image: 100^{th}] candy bar to make sure it is very close to the published weight.
A: a) weight of the candy bars b)Quantitative c)continuous
Feedback ("a) weight of the candy bars b)Quantitative c)continuous"): 1. VARIABLE: weight of the candy bars 2. TYPE: Quantitative. It is continuous. The weights could be any weight reasonably close to the desired weight due to variation in the number and weight of individual candies. Note: if the worker decided to sort the candy bars as acceptable, too light, or too heavy, the same scenario could include a categorical variable.

Q: For the situation described
a) describe the variable
b) tell if the variable is categorical or quantitative
c) if the variable is quantitative, then describe it further as either continuous or discrete.

Doris decides to clean her sock drawer out and sorts her socks into piles by color.
A: a) color of socks b) catgorical

Q: For the situation described
a) describe the variable
b) tell if the variable is categorical or quantitative
c) if the variable is quantitative, then describe it further as either continuous or discrete.
Note: There are 2 variables for this situation.

A researcher is studying the effect of a new drug treatment for diabetes patients. She performs an experiment on [Image: 200] randomly chosen individuals with Type II diabetes. Because she believes that men and women may respond differently, she records each person’s gender, as well as their change in sugar level after taking the drug for a month.
A: a) chang in sugar level b) quantitative c) continuous / a) gender b) categorical

Q: Choose the best guess for Pearson's correlation for the scatter plot.
[Image]
- -0.57
- -0.24
- 0.10
- 0.43
- 0.76
A: -0.57

Q: Choose the best guess for Pearson's correlation for the scatter plot.
[Image]
- -0.65
- -0.32
- 0.02
- 0.35
- 0.68
A: 0.02

Q: Choose the best answer for Pearson's correlation for the scatter plot.
[Image]
- -0.51
- -0.18
- 0.16
- 0.49
- 0.82
A: -0.51

Q: Choose the best answer for Pearson's correlation for the scatter plot.
[Image]
- -0.53
- -0.19
- 0.14
- 0.47
- 0.81
A: 0.47

Q: Choose the best answer for Pearson's correlation for the scatter plot.
[Image]
- -0.67
- -0.34
- 0.00
- 0.33
- 0.66
A: 0.66