Answer:
Explanation:
First, let's do the easy part of finding the mean.
we have 5 integers so we add everything in our set and divide by 5.
9+7+7+7+0 = 30 now we shouldn't forget to divide by 5 and 30/5 = 6
The mean is 6 and we rule out options A and C.
The standard deviation is found by doing the following steps:
1. Get the mean of the set (6)
2. subtract each number in the set from the mean and then square the result.
(6-9)^2 = 9
(6-7)^2 = 1
(6-7)^2 = 1
(6-7)^2 = 1
(6-0)^2=36
3. Now, find the mean of the numbers we just got.
9+1+1+1+36 = 48 Now we divide by 5 because of the number of digits in our set. 48/5 = 9.6
4. Finally, we square root 9.6 and we get about 3.1.
The answer is D.