The typical amount of sleep per night for undergraduate college students has a bell shaped distribution with a mean of 7 and a standard deviation of 1.90 hours. Based on this distributional information we can conclude that at least 95 % of this population sleep between___and_______hours a night

Answer 1

Z = (score-mean)/SD

Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion/probability (±.4750) and the related Z scores. Insert Z scores both into the equation above.