A company knows that replacement times for the quartz time pieces it produces are Normally distributed with a mean of 12 years and a standard deviation of 2.3 years.

Find the proportion of a randomly selected quartz time pieces that will have a replacement time less than 6.7 years?

P(X< 6.7 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.