Question 923875: The random variable x has a normal distribution with U=300 and standard deviation=30.
A. Find the probability that x assumes as value more than two standard deviations from its mean. More than three standard deviations from U.
B. Find the probability that x assumes a value within one standard deviation of its mean. Within two standard deviations of U.
C. Find the value of x that represents the 80th percentile of this distribution. The 10th percentile.
Answer by ewatrrr(24785)   (Show Source):
You can put this solution on YOUR website!
Using TI or similarly Your Casio fx-115 ES
A. P(z < -2 or x > 2) = 1- normalcdf(-2,2) = 1 - .9545 = .0455
P(z < -3 or x >3) = 1- normalcdf(-3,3) = 1 - .9973= .0027
........
B. P( -1 < z < 1) = normalcdf(-1,1) = .6827
P( -2 < z <2) = normalcdf(-2,2) = .9545
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