# top 30 percent ??

• December 3rd 2012, 10:25 AM
ashleyb
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?
• December 3rd 2012, 12:04 PM
MarkFL
Re: top 30 percent ??
Are you sure that is the correct standard deviation? 0.48 seems more likely to me.
• December 3rd 2012, 12:14 PM
ashleyb
Re: top 30 percent ??
whoops, the standard deviation is 1.401
• December 3rd 2012, 12:29 PM
MarkFL
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:

$x=z\sigma+\mu$