SOLUTION: Given the IQ scores are normally distributed with a mean 100 and a standard deviation of 10, A) find the probability that a randomly selected person has an IQ greater than 117.

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Question 815385: Given the IQ scores are normally distributed with a mean 100 and a standard deviation of 10,
A) find the probability that a randomly selected person has an IQ greater than 117.
B) find the probability that of 49 randomly selected people, their average IQ is less than 105.
Thank you!
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!
 

Hi, Re reply: P(z ≤ 1.7)= NORMSDIST(1.7)(Excel)  

0rP(z ≤ 1.7)=  normalcdf(-10,1.7)(TI Calculator) See Graph Below

 z = (117-100)/10 = 1.7.  P(z>1.7)  = 1 - P(z ≤ 1.7) = 1 - .9554 = .0446 0r 4.46% 

B) find the probability that of 49 randomly selected people, their average IQ is less than 105.

 z = %28105-100%29%2F%2810%2Fsqrt%2849%29%29+=+35%2F10+=+3.5

P(z ≤ 3.5) = .9554  0r  95.54%



z = 1.7

Note: P(z ≤ 1.7) is the Area under the Normal Curve to the 'left' of Blue Line

P(z > 1.7)is the Area under the Normal Curve to the 'right' of Blue Line