Which correlation coefficient should we use if we want to find out whether a relationship exists between two variables that are both interval or ratio variables?
a. The Pearson correlation coefficient
b. The Spearman rank-order correlation coefficient
c. The point-biserial correlation coefficient
d. The nonlinear correlation coefficient
Question 2In general, a zero correlation means that
a. as the values of one variable increase, there is no tendency for the values of the other variable to change in any consistent, predictable fashion.
b. as the values of one variable increase, there is a tendency for the values of the other variable also to increase.
c. as the values of one variable increase, there is a tendency for the values of the other variable to decrease.
d. as the values of one variable decrease, there is a tendency for the values of the other variable also to decrease.
Question 3A weak relationship between two variables is represented by
a. a small spread of Y scores at each X score.
b. a large spread of Y scores at each X score.
c. only one value of Y at each X score.
d. an equal spread of Y scores at each X score.
Question 4When the correlation coefficient representing the relationship between X and Y is intermediate, then all of the following are true except
a. there is not a perfectly consistent association.
b. there are different Y scores associated with a single X score.
c. prediction of Y from a known X score has some error.
d. all data points fall on the regression line.
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