The mean lifetime for a car battery is 180 weeks with a stan

The mean lifetime for a car battery is 180 weeks, with a standard deviation of 15 weeks. Assuming a normal distribution, what is the probability that the measured lifetime of a randomly chosen car battery is greater than 195 weeks?

A. 0.3413 C. 0.1587
B. 0.0228 D. 0.6826

Solution

Normal Distribution
Mean ( u ) =180
Standard Deviation ( sd )=15
Normal Distribution = Z= X- u / sd ~ N(0,1)                  
P(X > 195) = (195-180)/15
= 15/15 = 1
= P ( Z >1) From Standard Normal Table
= 0.1587