Given:
The data set of the monthly rent paid by 7 tenants
990, 879, 940, 1010, 950, 920, 1430
We will find the mean of the data:
Mean = Sum/n
n = 7
Sum = 990+879+940+1010+950+920+1430 = 7119
Mean = 7119/7 = $1017
One of the tenants change from 1430 to 1115
The mean after the change will be as follows:
Sum = 990+879+940+1010+950+920+1115 = 6804
n = 7
Mean = 6804/7 = 972
So, the answer will be:
Mean before the change = 1017
Mean after the change = 972