# Thread: top 30 percent ??

1. ## top 30 percent ??

you are a member of an orginization that awards money to the top students. with a mean of 1.9112, a standard deviation of 4.8, you want to choose the top 30% of students with the highest GPA. what is the minimum GPA of the students eligible for a scholarship?

2. ## Re: top 30 percent ??

Are you sure that is the correct standard deviation? 0.48 seems more likely to me.

3. ## Re: top 30 percent ??

whoops, the standard deviation is 1.401

4. ## Re: top 30 percent ??

You want to find the $z$-score associated with an area of 0.7 to the left of it. Consult your table for this. You may have to extrapolate.

Once you have this, then convert to an $x$-value using:

$x=z\sigma+\mu$