Use the information in below to answer Question 1. It represents the average time for a single company to

manufacture custom tools for use in producing semiconductors at two different locations:

Data Set 1 Data Set 2

Denton, TX Lincoln, NE

x = 57.7 hours x = 70.4 hours

S1 = 7.1 hours S2 = 8.3 hours

n1 = 15 n2 = 15

1. Assuming that the populations in Table 1 are normally distributed (allowing the use of the Z

distribution) with equal population variances, which answer is closest to the 95% confidence interval

estimate?

a) -19.47 < 1 - 2 < -7.93

b) -29.47 < 1 - 2 < 2.07

c) -39.47 < 1 - 2 < 12.07

d) -49.47 < 1 - 2 < 22.07