This is my first stats class and I don't know how to do this, could you please help me? Thank you.

Question

You are asked to determine the typical number of sales of a certain product at the store you work for. A sample of 50 days over the last quarter shows an average of 55 units sold per day with a standard deviation of 10 units.
a. Construct a 95 percent confidence interval around the mean.
b. Construct a 99 percent confidence interval around the mean.
c. Show the two limits on a graph of some sort
d. Interpret your results