# Easy sampling distribution question

• Oct 22nd 2011, 09:07 AM
youngb11
Easy sampling distribution question
An accounting professor claims that no more than one quarter of the undergraduate business students will major in accounting. What is the probability that in a random sample of 1,200 undergraduate students, 336 or more will major in accounting?

Not sure how I'd answer this. Answer in the book is 0.009. Any and all help appreciated!
• Oct 22nd 2011, 10:00 AM
TKHunny
Re: Easy sampling distribution question
We need assumptions for Mean and Variance. Since we have NO other information, let's go with AP's maximum claim of 0.25.

This gives:

Mean = 1200*0.25 = 300

Standard Deviation = $\displaystyle \sqrt{300*0.75} = 15$

Now what? Shall we use a Normal Approximation?
• Oct 22nd 2011, 10:47 AM
youngb11
Re: Easy sampling distribution question
Quote:

Originally Posted by TKHunny
We need assumptions for Mean and Variance. Since we have NO other information, let's go with AP's maximum claim of 0.25.

This gives:

Mean = 1200*0.25 = 300

Standard Deviation = $\displaystyle \sqrt{300*0.75} = 15$

Now what? Shall we use a Normal Approximation?

Thanks, I think I get it now:)