1. Given n=50, x =250, s=4, 90% confidence. Assuming that the samples come from a normal distribution, find the interval estimate of the population mean.

Select one:

a. (244.71, 248.74)

b. (248.35, 251.65)

c. (263.08, 264.67)

d. (249.07, 250.93)

2. Given n=20, x =30, s=2, 90% confidence. Assuming that the samples come from a normal distribution, find the margin of error.

Select one:

a. 0.74

b. 0.34

c. 0.56

d. 0.92

3. Given n=20, x =89, s=2, 99% confidence. Assuming that the samples come from a normal distribution, find the margin of error.

Select one:

a. 0.93

b. 1.05

c. 0.89

d. 1.15