Answer:
Relative frequency for each discount :
10% - 0.4925, 20% - 0.3325, 40% - 0.175
Since only 33.25% of customers got 20% discount, it is not an appropriate method.
Explanation:
relative frequency = number of frequency/total number of frequency
you can find out relative frequency for each number and add them up to get relative frequencies of discounts.