SOLUTION: Using diaries for many weeks, a study on the lifestyles of visually impaired students was conducted. The students kept track of many lifestyle variables including how many hours of

Question 1138409: Using diaries for many weeks, a study on the lifestyles of visually impaired students was conducted. The students kept track of many lifestyle variables including how many hours of sleep obtained on a typical day. Researchers found that visually impaired students averaged 9.25 hours of sleep, with a standard deviation of 2.51 hours. Assume that the number of hours of sleep for these visually impaired students is normally distributed.
Thirty percent of students get less than how many hours of sleep on a typical day?
answer:
hours
Answer by Boreal(15235) (Show Source): You can put this solution on YOUR website!
z for 0.3000=-0.525
z=(x-mean)/sd
=(x-9.25)/2.51
so -1.32=x-9.25
x=7.93 hours
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