Causality and Response Variable Changes

AP Statistics Name ____________________________________________
Chapter 4 Practice Test

Part I - Multiple Choice
1. Suppose that the scatterplot of (log x, log y) shows a strong positive correlation Which of the following must be true?

I. The variables x and y also have a correlation close to 1.
II. A scatterplot of (x, y) shows a strong nonlinear pattern.
III. The residual plot of the variables x and y shows a random pattern.

(a) I only
(b) II only
(c) III only
(d) I and II
(e) I, II, and III

2. What is the purpose of residual plots?

(a) To determine causation.
(b) To assess the type of relationship that exists between x and y.
(c) To check the appropriateness and fit of the regression equation for the data.
(d) To measure the variability in the residuals.
(e) To provide predictions for the response variable.

3. Fourth grade children were asked what emotion they associated with the color red. The responses for emotion and gender of the children are summarized in the following two-way table.

Anger
Pain
Happiness
Love
Male
35
27
12
38
Female
27
17
19
39

What proportion of the males associate the color red with love?
(a) 0.5234
(b) 0.3598
(c) 0.3393
(d) 0.1822
(e) 0.1775

4. A strong negative linear relationship between Average State SAT scores and Percentage of students taking the SAT in each of those states reflects which underlying relationship?

(a) causation
(b) correlation
(c) common response
(d) extrapolation
(e) confounding

5. Two variables are confounded when:

(a) The effect of one variable on the response variable is dependent upon the effect of the other variable.
(b) The effect of one variable on the response variable cannot be separated from the other variable.
(c) The effect of one variable on the response variable changes the impact of the other variable on the response variable.
(d) Both variables are classified as lurking or extraneous