Question 795308
Suppose the replacement times for washing Machines are normally distributed with a mean of 9.3 years and a standard deviation of 1.1 years. Find the probability that 70 randomly selected washing Machines will have a mean replacement time less than 9.1 years.
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z(9.1) = (9.1-9.3)/(1.1/sqrt(70)) = -0.2/(0.1315) = -1.5209
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P(x-bar<9.1) = P(z<-1.5209) = normalcdf(-100,-1.5209)= 0.0641
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Cheers,
Stan H.
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