VERY EASY An arcade manager wants to know how many of his 750 regular customers prefer to visit in the winter. Each of five staff members randomly surveys 25 regular customers. The table shows the results.

Preferred Season to Visit Arcade
Spring Sumer Fall Winter
A 4 4 6 11
B 5 3 7 10
C 5 5 5 9
D 4 5 6 10
E 4 4 5 12

a. Use each sample to make an estimate for the number of regular customers who prefer to visit in the winter.

b. Describe the variation of the estimates.