SOLUTION: is known that the time it takes to mark assignments are normally distributed with a population
standard deviation of 3.5 minutes. If a random sample of 81 assignments should be
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standard deviation of 3.5 minutes. If a random sample of 81 assignments should be
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Question 1195926: is known that the time it takes to mark assignments are normally distributed with a population
standard deviation of 3.5 minutes. If a random sample of 81 assignments should be marked, what is
the probability that the average time to mark these assignments will differ by no more than 1.2
minutes in either direction from the unknown population Answer by Boreal(15235) (Show Source):
You can put this solution on YOUR website! the sd of the sample distribution with n=81 is 3.5/sqrt(81)=0.39
1.2/0.39=3.076
probability of being in that interval is 0.9979
