Question

You have a normal distribution of hours per week that music students practice. The mean of the values is 8 and the standard deviation of the values is 4.

According to the normal distribution model that corresponds to this population, what percentage of the students practice between 6 to 10 hours per week?

Answer 1

first you find the z scores...

Answer 2

\[
z = \frac{x-\mu}{\sigma}
\]So \(\mu\) is average, \(\sigma\) is the standard deviation, and \(x\) is the value.

Answer 3

so you need to find \(z\) that corresponds to 6 and the \(z\) that corresponds to 10.

Answer 4

Would u be 16?

Answer 5

I think the answer is 34?

Answer 6

wait, have you found the z scores yet?

Answer 7

34%

Answer 8

where are you stuck? how did you get the answers?

Answer 9

Yeah 16 right? I'm estimating

Answer 10

Okay I think I've figure it out thanks for the help

Answer 11

oh, you are guessing because it is withing a standard deviation?

Answer 12

Yeah

Answer 13

okay you wanna do this:

http://www.wolframalpha.com/input/?i=within+half+standard+deviation

Answer 14

it should be 'confidence level'

Answer 15

Oh I see thanks!

Answer 16

So the answer is 38%

Answer 17

Yeah, I think so.