Question 298155
What is the probability that the random variable is less than or equal to 75 if the mean is 20 and the standard deviation is 4?
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Find the z-value of 75:
z(75) = (75-20)/4 = 55/4 = 13.75
Note: That means 75 is 13.75 standard deviations above the mean.
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P(x<= 75) = P(z <= 13.75) = 1 on my calculator
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Cheers,
Stan H.