Question

A manufacturer knows that their items have a normally distributed length, with a mean of 11.5 inches, and standard deviation of 1.7 inches.

If 6 items are chosen at random, what is the probability that their mean length is less than 13.2 inches?

Round your answer to four places after the decimal.

Answer 1

Answer

It is given that

(population mean)

(population standard deviation)

sample size n = 6

(sample mean)

we have to find the probability that mean length is less than 13.2 inches

setting the given values, we get

{using z table, check for 2.4 in left most column and 0.05 in the top most row, select intersecting cell}

So, required probability that the mean length is less than 13.2 inches is 0.9929 (rounded to 4 decimals)