For those who are good with math...?

Question

"The serum cholesterol levels for men in one age group are normally distributed with a mean of 178.1 and a standard deviation of 40.7. All units are in mg/100mL. Find the two levels that separate the top 9% and the bottom 9%."

That's a question on my take home statistics exam...the only one i can't figure out! The Z-scores i got for both the bottom and top %s are too similar to make any sense to continue on in figuring it out. Help!

Answer 1

One Z score should be positive and the other number the negative of the first.