SOLUTION: A standardized test measuring mathematics proficiency in sixth graders is administered nationally. The results show a normal distribution of scores with µ = 50 and Ơ = 5.8. If

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Question 978629: A standardized test measuring mathematics proficiency in sixth graders is administered nationally. The results show a normal distribution of scores with µ = 50 and Ơ = 5.8. If one score is randomly sampled from this population what is the probability it will be
a. Higher than 62?
b. Between 40 and 65?
c. Lower than 45?

Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
z=(score-mean)/sd
a) z= 12/5.8 or 2.07. Prob z>2.07=0.019
b.This is the probability of a z score of -1.724 and 2.586, -10/5.8 and 15/5.8
It should be very large. It is 0.9519
c. z must be less than -5/5.8 ;; z<-0.8621;; probability is 0.1943