5) 10 pts construct and interpret the indicated confidence interval for the
ditterence between the two population means. assume that the two samples are
independent simple random samples selected from normally distributed
populations. you can use s-pooled, or not pooled by your choice.
a paint manufacturer wanted to compare the drying times of two different
types of paint. independent simple random samples of 11 cans of type a and 9
cans of type b were selected and applied to similar surfaces. the drying times,
in hours, were recorded. the summary statistics are as follows.
type a
*1 = 71.5 hrs
51 = 3.4 hrs
m=11
type b
x2 = 68.5
hrs
s2 = 3.6 hrs
n2=9
construct, and interpret a 99% confidence interval for u1 - 42, the difference
between the mean drying time for paint type a and the mean drying time for
paint type b.
a) -2.24 hrs b) -1.00 hrs c) -0.14 hrs d) -1.51 hrs