A P/OM student has purchased a four-function calculator for use during exams.This calculator is perfectly reliable except for two parts: its microchip,which has a failure rate of one in every twenty hours of operation; and its battery,which has a failure rate of one in every ten hours of operation.Also,on average the battery will fail in five hours,with a standard deviation of 30 minutes.What is the probability that a new battery will fail within six hours?
A)0.0228
B)0.4772
C)0.5
D)0.9544
E)0.9772

Question

Quizplus · Accepted Answer

The battery life is normally distributed with a mean of 5 hours and a standard deviation of 0.5 hours (30 minutes). To find the probability of failure within 6 hours, calculate the Z-score: Z = (6 - 5) / 0.5 = 2. Using the standard normal distribution table, the probability of Z being less than 2 is approximately 0.9772.

A P/OM Student Has Purchased a Four-Function Calculator for Use