Question
A manufacturer knows that their items have a normally distributed length, with a mean of 12.9 inches, and standard deviation of 2.6 inches.
If 20 items are chosen at random, what is the probability that their mean length is less than 14.2 inches?
If 20 items are chosen at random, what is the probability that their mean length is less than 14.2 inches?
Answers
PsyDAG
Z = (score-mean)/SD/√n
Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion/probability for the Z score.
Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion/probability for the Z score.