If the student ratings of the overall effectiveness of professors is normally distributed with a mean of 5 and a standard deviation of 1.75, what proportion of the professors will be expected to be rated below 2.55?

Answer 1

This is a z-score
z=(x-mu)/(standard deviation)
z=(2.55-5)/(1.75)
find z then look it up on your "areas under the curve normal distribution table" in the back of your textbook : )