6. Consider H0: = 45 versus H1: < 45. A random sample of 25 observations produced a sample mean of 41.8. Using = .025 and the population is known to be normally distributed with = 6.

1. What is the value of z? Round to two decimal places.
2. Would you reject the null hypothesis?
3. Reject Ho
4. Do not reject Ho

7. The following information is obtained from two independent samples selected from two normally distributed populations.

n1 = 18x1 = 7.821 = 2.35

n2 =15 x2 =5.992 =3.17

A. What is the point estimate of 1 2? Round to two decimal places.

B. Construct a 99% confidence interval for 1 2. Find the margin of error for this estimate.

Round to two decimal places.

8. The following information is obtained from two independent samples selected from two

populations.

n1 =650x1 =1.05 1 =5.22

n2 =675x2 =1.542 =6.80

Test at a 5% significance level if 1 is less than 2.

a)Identify the appropriate distribution to use.

1. t distribution
2. normal distribution

b)What is the conclusion about the hypothesis?

A.Reject Ho

B.Do not reject Ho