For a particular brand of potato chips, a market research institute determines a high correlation coefficient—r = (0.7383)—between sales and price. Accidentally, they also discover a weak association—r = (+0.3347)—between potato chips sales and toilet paper price.

(a) How should we interpret the correlation coefficient of r = 0.3347 for potato chip sales and toilet paper price?

(b) Calculate the partial correlation coefficient between potato chip sales and toilet paper price to the nearest thousandth and controlled for the potato chip price. The correlation between toilet paper price and potato chip price is r = (-0.4624).

(c) How should we interpret the results?