Question: Compute confidence intervals for the onesample z test, the one-sample t test, the two-independent-sample t test, and the related-samples t test.

• The three steps to estimation are as follows:

Step 1: Compute the sample mean and standard error.

Step 2: Choose the level of confidence and find the critical values at that level of confidence.

Step 3: Compute the estimation formula to find the confidence limits.

The estimation formula for the onesample z test isM± z(crM).

• The estimation formula for each t test is as follows: One-sample t test: M ± t(sM). Two-independent-sample t test: Mt- M2 ± t(sMt-M2). Related-samples t test: MD± t(sMD)