Question 1

Bob is interested in how much community college students work outside of school. Bob decides to ask the students in his psychology class, including his own question: 'How many hours did you work in the last two weeks?' and records the value. What type of variable is Bob collecting?

Accepted Answer

Quantitative variable

Question 2

In the study where Ella wants to know if plants will grow faster if they listen to Taylor Swift music, what is the explanatory variable?

Accepted Answer

Whether or not the plant listens to music

Question 3

Which of the following best describes an observational study?

Accepted Answer

The researcher collects data without manipulating any variables.

Question 4

Given the exam scores: 82, 72, 68, 78, 96, 100, 92, 100, 89, 88, what is the mean score? (Round to 1 decimal place)

Accepted Answer

$$ 86.5 $$

Question 5

Given the same exam scores, what is the median?

Accepted Answer

$$ 88.5 $$

Question 6

A histogram of recent college graduates' reported salaries is right-skewed. Which measure of central tendency is most appropriate to report?

Accepted Answer

Median, because it is resistant to outliers

Question 7

A graph shows the percentage of respondents who support background checks for all gun buyers, but the vertical axis does not start at zero. Why is this misleading?

Accepted Answer

It exaggerates the differences between groups

Question 8

Jimmy wants to know how all Americans feel about debt-relief programs for people with student loans. He surveys people in the student lounge on campus. What is the main problem with his sample?

Accepted Answer

It is not representative of all Americans

Question 9

Scientists want to determine the effect of smoking tobacco around newborns. Which study design is most ethical?

Accepted Answer

Observational study

Question 10

Professor Jones' students finish the semester with a mean score of $$80$$ and a standard deviation of $$5. $$According to the Empirical Rule, what range of grades would you expect 95% of students to fall in?

Accepted Answer

$$ 70  to$$ $$ 90 $$

Question 11

Given the regression equation $$ y = 0.1337x + 12.471 $$, what does the slope $$ 0.1337 $$ represent in the context of predicting a child's head circumference from their height?

Accepted Answer

For each additional inch in height, head circumference increases by $$ 0.1337 $$ inches

Question 12

If the correlation coefficient $$ r $$ between two variables is $$ 0.91 $$, what does this indicate?

Accepted Answer

A strong positive linear relationship

Question 13

Which of the following is NOT a reason to use the median instead of the mean as a measure of central tendency?

Accepted Answer

The data are symmetric

Question 14

Given the data set: $$ 82, 72, 68, 78, 96, 100, 92, 100, 89, 88 $$, what is the range?

Accepted Answer

$$ 32 $$

Question 15

A boxplot is useful for which of the following purposes?

Accepted Answer

Displaying the five-number summary and identifying outliers

Question 16

If a data set has a strong negative association, what does this mean?

Accepted Answer

As one variable increases, the other variable decreases

Question 17

Which of the following is a potential outlier in a data set?

Accepted Answer

A value that is much higher or lower than the rest of the data

Question 18

If $$ Q_1$ = 78 $$ and $$ Q_3$ = 96 $$, what is the interquartile range (IQR)?

Accepted Answer

$$ 18 $$

Question 19

Which of the following best describes a designed experiment?

Accepted Answer

The researcher intentionally manipulates the explanatory variable and controls other variables

Question 20

If a student scores $$ 2.8 $$ standard deviations above the mean on an exam, how would you describe this score?

Accepted Answer

It is unusual

Step-by-Step Guidance for Descriptive Statistics Exam Study

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