Construct the indicated confidence interval for the differencebetween the two population means.
Assume that the two samples are independent simple random samplesselected from normally
distributed populations. Do not assume that the population standarddeviations are equal. A paint
manufacturer wished to compare the drying times of two differenttypes of paint. Independent
simple random samples of 11 cans of type A and 9 cans of type Bwere selected and applied to
similar surfaces. The drying times, in hours, were recorded. Thesummary statistics are as follows.
Type A
Xba = 75.7 hrs.
s1 = 4.5 hrs.
n1 = 11
Type B
Xba = 64.3 hrs.
s2 = 5.1 hrs.
n2 = 9
Construct a 98% confidence interval for μ1 - μ2, the differencebetween the mean drying time for
paint of type A and the mean drying time for paint of type B.
4)
A) 6.08 hrs < μ1 - μ2 < 16.72 hrs B) 5.85 hrs < μ1 - μ2< 16.95 hrs
C) 5.92 hrs < μ1 - μ2 < 16.88 hrs D) 5.78 hrs < μ1 - μ2< 17.02 hrs
