Homework Help: statistics

Posted by tara on Saturday, May 12, 2012 at 10:00pm.

suppose the replacement times for washing machines are normally distributed with mean 8.6 years and standard devistion of 1.6years.
a. what percentage of washing machines have replacement times less than 7 years?
b. find the probability that a washing machine will have a replacement time of more than 6.5 years?

statistics - PsyDAG, Sunday, May 13, 2012 at 12:21pm
Z = (score-mean)/SD

Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportions related to the Z scores.

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