All but one of the statements below contain a mistake.Which one could be true?
A)If the correlation between blood alcohol level and reaction time is 0.73, then the correlation between reaction time and blood alcohol level is -0.73.
B)The correlation between the breed of a dog and its weight is 0.435.
C)The correlation between gender and age is -0.171.
D)The correlation between height and weight is 0.568 inches per pound.
E)The correlation between weight and length of foot is 0.488.

Question

Quizplus · Accepted Answer

Correlation coefficients measure the strength and direction of a linear relationship between two variables on a scatterplot, ranging from -1 to 1. Choices A, B, C, and D are incorrect for the following reasons: A) Correlation is symmetric; the correlation from X to Y is the same as from Y to X, so if it's 0.73 in one direction, it's also 0.73 in the other, not -0.73. B) Correlation coefficients are between -1 and 1, but they cannot be calculated between categorical variables (like dog breeds) and numerical variables (like weight) using Pearson's correlation. C) Similar to B, gender is a categorical variable, making it inappropriate for Pearson's correlation with a numerical variable like age. D) Correlation coefficients do not have units (like inches per pound); they are unitless. E) is plausible because it describes a correlation between two numerical variables, which is how correlation coefficients are properly used.

All but One of the Statements Below Contain a Mistake