To determine if there is a linear relationship between two quantitative variables, which test would you use?

To determine if there is a linear relationship between two quantitative variables, which test would you use?

• A. 2-proportion z-test
• B. 1-proportion z-test
• C. Linear regression t-test
• D. Chi-square test of independence

Answer: (C)

Evaluating whether a straight-line relationship exists between two quantitative variables is done by fitting a linear regression model and testing whether the slope is zero. The linear regression t-test specifically tests the null hypothesis that the slope equals zero; if the slope is significantly different from zero, that indicates a linear relationship between the variables. The other tests aren’t designed for this purpose: tests for proportions deal with categorical outcomes, and the chi-square test of independence examines relationships between categorical variables.

Evaluating whether a straight-line relationship exists between two quantitative variables is done by fitting a linear regression model and testing whether the slope is zero. The linear regression t-test specifically tests the null hypothesis that the slope equals zero; if the slope is significantly different from zero, that indicates a linear relationship between the variables. The other tests aren’t designed for this purpose: tests for proportions deal with categorical outcomes, and the chi-square test of independence examines relationships between categorical variables.