Company XYZ know that replacement times for the quartz time pieces it produces are normally distributed with a mean of 11 years and a standard deviation of 2 years. Find the probability that a...

Company XYZ know that replacement times for the quartz time pieces it produces are normally distributed with a mean of 11 years and a standard deviation of 2 years.


Find the probability that a randomly selected quartz time piece will have a replacement time less than 6 years?


P(X
< 6="" years)="">



Enter your answer accurate to 4 decimal places. Answers obtained using exact
z-scores or
z-scores rounded to 3 decimal places are accepted.


If the company wants to provide a warranty so that only 0.9% of the quartz time pieces will be replaced before the warranty expires, what is the time length of the warranty?

warranty = years


Enter your answer as a number accurate to 1 decimal place. Answers obtained using exact
z-scores or
z-scores rounded to 3 decimal places are accepted.