Question

What is the variance of the following data? If necessary, round your answer to two decimal places.
9, 10, 10, 8, 7, 11, 12, 9


2.25

3.45

5.67

5.89

Answer 1

First find the expected value:
\[1/n (0 + 1 + 2 + 3 + 4.....+n)\]
where 0, 1, 2, 3, 4, etc... are the elements of the set and 'n' is the number of elements in the set.

Answer 2

i dnt understand

Answer 3

First, find the average of each of the elements.\[\frac{9+10+10+...}{8}\]Second, find the average of the squares of each of the elements. \[\frac{9^2+10^2+10^2+...}{8}\]The 8 on the bottom is because there are 8 elements.

Answer 4

so i do the number squared and just add them all like that then divide by 8

Answer 5

Yeah, that is how you get to the average of the squares. Then, to get the variance you take:
(the average of the squares) - the square of the average

Answer 6

okaii thank yu is that all i need too know

Answer 7

So if my numbers were 1, 2, 3, 4 the average would be 2.5. The average of the squares would be (1+4+9+16)/4 = 7.5 and the variance would be 7.5 - (2.5)^2 = 1.25

Answer 8

i tried doing what you said the answer didnt come out right