An electronics store kept track of the number of headsets sold during one week to determine how many headsets they should have in stock each day. Here is their data: $15$ headsets sold on Monday, $23$ on Tuesday, $15$ on Wednesday, $20$ on Thursday, $42$ on Friday, $58$ on Saturday, and $48$ on Sunday.

1. Is there a difference between the sale of headsets on the weekdays (Monday through Friday) and the sale of headsets on the weekend days (Saturday and Sunday)? Explain your thinking.

   Hint (a):

   Separate the data into weekday data and weekend data. This will help you in making the comparison.

2. Calculate the mean of sales on weekdays and the mean of sales on the weekend and show how the difference in means confirms your thinking in part (a).

   Hint (b):

   Remember that the mean, in this case, is the number of headsets sold each day, if they sold the same
   number each day. You need to find two means, one for the weekdays' sales and one for the weekend's sales.

   More Help (b):

   Refer to problem 1-112 if you need additional help finding the mean.