The question reads, What is the standard deviation for the sample data below: 154,216,171,188,229,203,184,173,181,147
Round the answer to the nearest tenth.


I have done this several times but my answer keeps coming up wrong. Can anyone explain this to me>?

Well, I did the problem with my calculator to make sure it was accurate, and I got the answer of 24.475.

If that is not the correct answer... maybe the key is wrong :)
(or I could be wrong too!)
Hope that helped!

Must you do it without the benefit of using a scientific calculator (most of which have a built-in feature than can automatically calculate a standard deviation)? In other words, must you show that you know how to apply the formula for calculating a standard deviation? If so, then proceed as follows:

1. calculate the mean
2. subtract the mean from each item in your list and note each difference
3. square each difference
4. calculate the mean of these differences
5. take the square root of the result. This square root is the standard deviation.

The steps you listed are correct. Maybe if you list what you got on each step, we'll be able to find out where you went wrong.