Use the mean and standard deviation of a data set to fit it to a normal distribution and to estimate population percentages.

Question

The ACT is an exam used by colleges and universities to evaluate undergraduate applicants. The test scores are normally distributed. In a recent year, the mean test score was 22.2 and the standard deviation was 4.9. The test scores of four students selected at random are 15 and 28.

a) Find the z-scores that correspond to each value.

b) Determine whether any of the values are unusual. (Two standard deviation

above or below the mean.)

Answer 1

Hi Eddie Z.,

You've asked 4 questions at the same time on essentially the same topic and requiring the same skills to solve. That's spamming; we're not here to solve your entire problem sets for you. Please cut your questions down to one (the hardest, perhaps?) and someone will undoubtedly help you!

-- Cheers, --Mr. d.