The population of lengths of aluminum-coated steel sheets is normally distributed with a mean of 30.05 inches and a standard deviation of 0.2 inches.What is the probability that a sheet selected at random will be less than 31 inches long?
A)0.00
B)1.00
C).8289
D).5987

Question

Quizplus · Accepted Answer

Since the mean is 30.05 inches and the standard deviation is 0.2 inches, a length of 31 inches is 4.75 standard deviations above the mean. In a normal distribution, almost all values lie within 3 standard deviations of the mean, so the probability of a value being less than 31 inches is essentially 1.00.

The Population of Lengths of Aluminum-Coated Steel Sheets Is Normally