Freshman-sophomore retention rate (FSRR) for a college is the proportion of first-year students who return to the college for their sophomore year. Nationwide, the mean FSRR for colleges in the U.S. is 75%. Use the 68-95-99.7 rule to describe graphically the sampling distribution for the FSRR at college with entering classes of 400.
SD(p-hat)= sq. root of [(0.75*0.25)/400]= 0.022
So z= p-hat - p /SD(p-hat)
= ? - 0.75/0.022
I'm not sure what the first # should be where the ? mark is. In the book it gives it as like the proportion of say 15 out of 90 people are lefties. But I don't know about this problem. Please help ASAP!
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