Question

Retrenched Auto Body management wonders if the satisfaction rate (in %) of their customers depends on the length of time it takes to repair the automobile (in weeks). They arbitrarily keep one car for one week, another car for two weeks, another for three, and still another for four weeks, and then have the cars’ owners report their percentage level of satisfaction. Ignoring history or other test effects, determine the following:

Customer	Repair time (weeks)	Satisfaction (%)	Repair-time squared	Satisfaction squared	Repair-timeX satisfaction
Randy	1	60	1	3600	60
Theo	2	55	4	3025	110
Kaylene	3	30	9	900	90
Al	4	15	16	225	60
sum	10	160	30	7750	320
average	2.5	40	7.5	1937.5	80

a. Compute (numerically) and interpret (in words) the correlation between satisfaction and repair time

b. Estimate the regression function between satisfaction and repair time

c. If they kept a car for six weeks, what satisfaction level would the regression function predict?

Answer 1

a)b)c) Y = 93.268+185.314(6) = 1205.152