Duplicate of Confidence Intervals

If you increase the sample size, the confidence interval gets

Find the 82% C.I. : n=40, sigma=10, x-bar=92

What is the margin of error for a 80% C.I. when sigma=10 and there is a sample size of 40 ?

What is the margin of error for a 95% C.I. when sigma=20 and there is a sample size of 30 ?

What sample size is needed for a margin of error within +/- 2, with sigma = 5 and 99% C.I. ?

What sample size is needed for a margin of error within +/- .5, with sigma = 2 and 90% C.I. ?