In: Statistics and Probability
Company XYZ know that replacement times for the quartz time
pieces it produces are normally distributed with a mean of 15.4
years and a standard deviation of 1.8 years.
Find the probability that a randomly selected quartz time piece
will have a replacement time less than 9.8 years?
P(X < 9.8 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 2.5% 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.