You wish to see if there is a difference in weight between the limes and lemons that are
sold at your grocery store. You know that the weights of each are normally distributed.
The population standard deviations are 50 grams for lemons and 40 grams for limes.
You sample 45 lemons, and find a sample average of 135 grams. You sample 55 limes,
and find a sample average of 140 grams. Perform a hypothesis test at the 0.05 level to
see if there is a difference in weight.