Company XYZ know that replacement times for the quartz time pieces it produces are normally distributed with a mean of 11.9 years and a standard deviation of 1.7 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 11.9 years and a standard deviation of 1.7 years.


Find the probability that a randomly selected quartz time piece will have a replacement time less than 8.3 years?

P(X < 8.3="" years)="">


Enter your answer accurate to 4 decimal places. Answers obtained using exactz-scores orz-scores rounded to 3 decimal places are accepted.


If the company wants to provide a warranty so that only 3.8% 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 exactz-scores orz-scores rounded to 3 decimal places are accepted.