Question

what is the standard deviation for 9,5,9,5,9,5,9,5

Answer 1

Which methods are you currently using to find standard deviation? By hand? Using a simple calculator? Using a calculator with statistics functions built in? Knowing this will help me decide how to respond to your question.

Answer 2

regular calculator

Answer 3

do you have some paper and a pencil handy? You'll need them.

Answer 4

yes

Answer 5

Add together these 8 numbers: 9,5,9,5,9,5,9,5. Divide the sum by 8. The result is the mean of your data set. What is it?

Answer 6

7

Answer 7

Right. Now I'm going to type in the formula for the standard deviation of a population:\[\sigma^2=\frac{ \sum_{1}^{n} (x-mean)^2}{ n }\]

Answer 8

Have you seen this before? Have you worked with it before?

Answer 9

Note that you have already found the mean: It is 7.