Question 1

Which of the following statements about scatterplots is TRUE?

Accepted Answer

A scatterplot allows you to spot outliers in the data.

Question 2

What does a negative correlation between two variables mean?

Accepted Answer

When one variable increases, the other variable tends to decrease.

Question 3

Refer to the scatterplot of 'Years of Education' (x-axis) and 'Salary (thousands of dollars)' (y-axis). Which of the following best describes the relationship?

Accepted Answer

There is a strong positive correlation between years of education and salary.

Question 4

The correlation coefficient $$r is $$always between which two values?

Accepted Answer

$$-1$$ and $$1$$

Question 5

A scatterplot shows points that are very close together and trend downward from left to right. Which correlation coefficient best matches this description?

Accepted Answer

$$r = -0.86$$

Question 6

Suppose the linear model for predicting soft drink price ($$y) $$from hot dog price ($$x) at $$MLB stadiums is $$y = 0.5x + 2. $$What is the predicted soft drink price at a stadium where a hot dog costs $$4$$?

Accepted Answer

$$y = 0.5 	imes 4 + 2 = 4$$

Question 7

Let $$w be $$the weight (in pounds) and $$h be $$the height (in inches) of a person. Which is the explanatory variable and which is the response variable?

Accepted Answer

Height is explanatory, weight is response.

Question 8

Given the ordered pair $$(66, 142) in $$the context of height and weight, what does this represent?

Accepted Answer

A person who is 66 inches tall and weighs 142 pounds.

Question 9

If $$t is $$the number of years since 2010, what value of $$t$$ corresponds to the year 2025?

Accepted Answer

$$t = 15$$

Question 10

True or False: An association between two variables always means that one variable causes the other.

Accepted Answer

False

Question 11

A traffic officer computes a correlation coefficient of $$r = 0.12$$ between hour of the day and speed over the limit. What does this tell the officer?

Accepted Answer

There is insufficient evidence to make any conclusions about the relationship between the variables.

Question 12

Suppose the number of bank robberies $$n in a $$year is modeled by $$n = -250t + 7500$$, where $$t is $$the number of years since 2000. According to this model, in what year were there approximately 4800 bank robberies?

Accepted Answer

$$t = 10.8$$, so the year is approximately 2011$

Question 13

Which of the following best describes the meaning of the intercept in a linear model predicting number of bank robberies from year?

Accepted Answer

The intercept is the predicted number of bank robberies when $$t = 0$$, i.e., in the year 2000.

Question 14

Which correlation coefficient best matches a scatterplot where the points are tightly clustered in an upward trend?

Accepted Answer

$$r = 0.98$$

Question 15

Which of the following is a correct interpretation of a correlation coefficient $$r = -0.03$$?

Accepted Answer

There is essentially no linear relationship.

Question 16

If the correlation between shoe size and height is $$r = 0.64$$, what does this indicate?

Accepted Answer

There is a moderate positive linear relationship.

Question 17

Which of the following statements is TRUE about correlation and causation?

Accepted Answer

Correlation does not necessarily imply causation.

Question 18

Suppose you observe a scatterplot with points scattered randomly and no apparent trend. What is the likely value of the correlation coefficient?

Accepted Answer

$$r is $$close to $$0$$

Chapter 6 Review: Scatterplots, Correlation, and Linear Models – Guided Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards