1.Find and interpret a 95% confidence interval for a population meanfor these values:

a.n= 36 xbar= 13.1 s2= 3.42

b.n= 64 xbar= 2.73 s2= 0.1047

2.Independent random samples of sizewere selected from each of two populations. The mean and standard deviations for the two samples werexbar1=125.2, xbar2=123.7, s1=5.6ands2=6.8.

a. Construct a 99% confidence interval for estimating the difference in the two population means.

b. Does the confidence interval in part a provide sufficient evidence to conclude that there is a difference in the two populations means? Explain

3.The followingobservations are a sample from a normal population:

7.47.16.57.57.66.36.97.76.57.0

a. Find the mean and standard deviation of these data.

b. Find a 99% confidence interval for the population mean. Interpret this interval.

4.Independent random samples ofandobservations were selected from two normal populations with equal variances:

Population

1 2

Sample Size 16 13

Sample Mean 34.6 32.2

Sample Variance 4.8 5.9

Find a 99% confidence interval for. What can you conclude?