For the past 90 days, daily sales of market umbrellas at a Florida Costco store have been recorded (to the nearest 10).

Units Sold	Number of Times
20	5
30	16
40	26
50	31
60	12

a. Determine the relative frequency for each number of units sold.

b. Suppose that the following random numbers were obtained using Excel:

0.87 0.07 0.94 0.70 0.51 0.46 0.05 0.34 0.96 0.55

Use these random numbers to simulate 10 days of sales. (SHOW EXCEL FORMULAS)