MATH
posted by Ty .
Battery Power Problem. A certain type of thermal battery
for an airplane navigation device backup power has a
mean life of 300 hours with a standard deviation of 15
hours. What proportion of these batteries can be
expected to have lives of 322 hours or less? Assume a normal
distribution of backup power device lives.

Z = (x  mean)/SD = (322300)/15
Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion below the Z score found from above.
Respond to this Question
Similar Questions

MATH Prob.
Battery Power Problem. A certain type of thermal battery for an airplane navigation device backup power has a mean life of 300 hours with a standard deviation of 15 hours. What proportion of these batteries can be expected to have … 
Math
A certain type of thermal battery for an airplane navigation device backup power has a mean life of 300 hours with a standard deviation of 15 hours. Assume a normal distribution of backup power device lives. What proportion of these … 
Math
A certain type of thermal battery for an airplane navigation device backup power has a mean life of 300 hours with a standard deviation of 15 hours. Assume a normal distribution of backup power device lives. What proportion of these … 
Teacher Math
Battery Power Problem. A certain type of thermal battery for an airplane navigation device backup power has a mean life of 300 hours with a standard deviation of 15 hours. What proportion of these batteries can be expected to have … 
Help Math!
Battery Power Problem. A certain type of thermal battery for an airplane navigation device backup power has a mean life of 300 hours with a standard deviation of 15hours. What proportion of these batteries can be expected to have lives … 
Statistics
The lifetime of a certain smart phone battery has an unknown distribution with mean value of 8 hours and standard deviation of 2 hours. What is the approximate probability that the average battery lifetime of a sample of 36 batteries … 
Statistics
The lifetime of a certain smart phone battery has an unknown distribution with mean value of 8 hours and standard deviation of 2 hours. What is the approximate probability that the average battery lifetime of a sample of 36 batteries … 
Statistics
Several states, including California, have passed legislation requiring automakers to sell a certain percentage of zeroemissions cars within their borders. One current alternative is batterypowered cars. The major problem with batteryoperated … 
Statistics
A company makes batteries with an average life span of 300 hours with a standard deviation of 75 hours. Assuming the distribution is approximated by a normal curve fine the probability that the battery will last . Less than 250 hours … 
Math
A company makes batteries with an average life span of 300 hours with a standard deviation of 75 hours. Assuming the distribution is approximated by a normal curve fine the probability that the battery will last:(give 4 decimal places …