Question 664955
The mean age at which men in the U.S. marry for the first time follows the normal distribution with a mean of 24.8 years. The standard deviation of the distribution is 2.5 years. For a random sample of 60 men, what is the likelihood that the age at which they were married for the first time is less than 25.1 years? 
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t(25.1) = (25.1-24.8)/[2.5/sqrt(60)] = 0.9295
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P(x-bar < 25.1) = P(t < 0.9295 when df = 59) = tcdf(-100,0.9295,59) = 0.8218
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Cheers,
Stan H.