question is below i am so lost

Question

A survey of grade point averages over the last 20 years is taken at Academy. It is found that the mean is 2.52, the median is 2.65, and the standard deviation is 0.55. Assuming a normal distribution, within what GPAs do 99.7% of the students fall?

Answer 1

since it is normal distribution, 99.7% of observation will fall within three standard deviations.

mean -3*stdev=2.52-3*0.55=0.87

mean +3*stdev=2.52+3*0.55=4.17

Students GPA will fall between   0.87  and    4.17.     .

Answer 2

99.7% of normally distributed data lies between z-scores -3 and 3.

 

That means GPA scores from 2.52 - 3(0.55) up to 2.52 + 3(0.55) embrace 99.7% of the entire populatlon tested.