a copy machine dealer has data on the number x of copy machines at each of 89 customers location in the number y of service calls in a month at each location. Summary calculations givex(bar)=8.4, s(sub x)=2.1, y(bar)=14.2, s(sub y)=3.8, and r=0.86.

about what percent of the variation in the number of service calls is explained by the linear relation between number of service calls and the number of machines?

a)86%

b)93%

c)74%

d)none of these

e)can't tell from the information given