Jed Home Stores analyzed the value of purchases made on credit card by a random sample of 25 of their credit customers. The sample mean was found to be R170, with a sample standard deviation of R22....

Jed Home Stores analyzed the value of purchases made on credit card by a random sample of 25 of their credit customers. The sample mean was found to be R170, with a sample standard deviation of R22.


a) Estimate, with 95% confidence, the actual mean value of credit card purchases by all their credit card customers.
b) Assume that 46 credit card purchases were sampled. Set 95% confidence limits for the actual mean value of credit card purchases at this home store (σ is unknown)