Question

The publisher of a regional telephone book surveyed a simple random sample of 10 of its commercial yellow-page ad customers to determine whether the size of their ads in square inches were correlated with the proportion of calls to the business that were generated by the ads.

a. Calculate the correlation coefficient

b. Calculate the coefficient of determination

What percentage of the variation in the proportion of calls generated by the ad is explained by the size of the ad in square inches?

Is the correlation coefficient significantly greater than zero at the 5% significance level?

Respondent #	Ad size in sq inches (X)	% of calls generated by the ad (Y)	X*Y	X2	Y2
1	9	13%	1.17	81	0.017
2	16	16%	2.56	256	0.026
3	25	21%	5.25	625	0.044
4	16	18%	2.88	256	0.032
5	20	18%	3.60	400	0.032
6	16	19%	3.04	256	0.036
7	20	15%	3.00	400	0.023
8	20	17%	3.40	400	0.029
9	16	13%	2.08	256	0.017
10	9	11%	0.99	81	0.012

Answer 1