# Another problem I started but cant finish

#### mathjunkie1990

##### New member
5. Assume that 35% of the students at a College play a musical instrument. We randomly choose 100 students.
a. What is the appropriate model for the distribution of the proportion of students in this sample who play a musical instrument? Specify the name of the distribution, the mean, and the standard deviation.
b. What is the approximate probability that more than 40% of the sample will play a musical instrument?

would you use the geometric probability model?

#### tkhunny

##### Moderator
Staff member
You started this by simply guessing? That's not much of a start.

Does the Geometric Distribution deal with Proportions of a Population?

You might want to think about the Binomial. p = 0.35 and n = 100

#### mathjunkie1990

##### New member
ok so using the binomial
mean= n*p=100*.35=35
stand.dev.=sqr.rt of n*p*q=sqr.rt of 100*.35*.65=sqr.rt.of 22.75=4.77

that answers part a so for part b would you just replace 35% with 40%

#### Jamieruss33

##### New member
For part B they are asking for MORE than 40%. I think that you would use the compliment method.

#### tkhunny

##### Moderator
Staff member
Maybe, or you could consider (40-35)/4.77 = 1.048 and how this value relates to the Standard Normal Distribution.

#### mathjunkie1990

##### New member
ok thank you for all the help =D

thanks