SOLUTION: No length of a lumber, a machine cuts are normally distributed by a mean of 89 inches and a standard deviation of 0.5 inch part a what is the probability that a randomly selected b
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Question 1201038: No length of a lumber, a machine cuts are normally distributed by a mean of 89 inches and a standard deviation of 0.5 inch part a what is the probability that a randomly selected board cut by the machine has a length greater than 89.12 inches part B hey sample of 41 boards is randomly selected what is the probability that their main length is greater than 89.12 inches Answer by Theo(13342) (Show Source):
You can put this solution on YOUR website! the lengths of lumber a machine cuts are normally distributed with a mean of 89 inches and a standard deviation of 0.5 inches.
part a:
what is the probability that a randomly selected board cut by the machine has a length greater than 89.12 inches.
part b:
what is the probability that a randomly selected sample of 41 boardshas a mean length greater than 89.12 inches.
answer to part a:
mean is 89 inches.
standard deviation is .5 inches.
probability that the board has a length greater than 89.12 inches is .4052.
answer to part b:
mean is 89 inches
standard deviation is .5
sample size is 41
standard error is .5 / sqrt(41) = .0780868809.
probability that the mean length of the sample will be greater thana 89.12 is .06217731.
when you are dealing with a sample of one element, use the standard deviation.
when you are dealing with the mean of a sample of more than 1 element, use the standard error.
the standard error is equal to the standard deviation divided by the square root of the sample size.
