# Fun HW question

#### skeepin32

##### New Member
So my prof is a big football fan
She wants us to take our favorite team and figure out the probability of in a random year our team winning 10 games.

I am taking the win total for 10 years, 20 years, and 42 years. Then I will find the mean and standard deviation of the win totals. I will have 3 answers based on 10, 20, and 42 years.

My win totals: (yeah my team isn't real good lol)
10 year: 55 mean 5.5
20 year: 132 mean 6.6
42 year: 270 mean 6.4

I am confused on finding the standard deviation...
Am I going to take each of the seasons win totals minus the mean and square it...then add them all together and divide by n-1? (would that be 10-1 and then 20-1 and 42-1?)

hopefully this makes sense...I didn't see it completely necessary to write out all my data..let me know if it is needed.

#### Mean Joe

##### TS Contributor
I am confused on finding the standard deviation...
Am I going to take each of the seasons win totals minus the mean and square it...then add them all together and divide by n-1? (would that be 10-1 and then 20-1 and 42-1?)
Yeah, you find the standard deviation in 3 situations. So you will find the probability based on 10 years data (where you have a sample mean & standard deviation that is based on those 10 years), on 20 years, and on 42 years.

Don't forget to square root for standard deviation, else you will be dealing with variance.