Please help me. I'm forgetting how to do this.

Suppose you have a sample size of 41 with a mean 65 and a population standard deviation of 6.8. Based on this, construct a 99% confidence interval for the true population mean. As in the reading, in your calculations: --Use z = 1.645 for a 90% confidence interval --Use z = 2 for a 95% confidence interval --Use z = 2.576 for a 99% confidence interval. Give your answers as decimals, to two places [ ], [ ]