A new-car dealer is interested in the relationship between the number of salespeople working on a weekend and the number of cars sold. Data were gathered for six consecutive Sundays: Number of...

A new-car dealer is interested in the relationship between the number of salespeople working on a weekend and the number of cars sold. Data were gathered for six consecutive Sundays:

(a) Determine the estimated regression line.

(b) What is the coefficient of determination?

(c) How much of the variation in the number of automobiles sold is explained by the number of salespeople?

(d) Test the null hypothesis that the mean number of sales does not depend on the number of salespeople working.