The lifetime of a certain type of battery is normally distributed with mean value 15 hours and standard deviation 1 hour. there are four batteries in a package. what lifetime value is such that the total lifetime of all batteries in a package exceeds that value for only 5% of all packages? (round your answer to two decimal places.)

If the lifetime of batteries in the packet is 40.83 hours or more then, it exceeds for 5% of all packages.

Step-by-step explanation:

We are given the following information in the question:

Mean, μ = 15

Standard Deviation, σ = 1

Sample size = 4

Total lifetime of 4 batteries = 40 hours

We are given that the distribution of lifetime is a bell shaped distribution that is a normal distribution.

Formula:

Standard error due to sampling:

We have to find the value of x such that the probability is 0.05

P(X > x)  = 0.05

Calculation the value from standard normal z table, we have,  

Hence, if the lifetime of batteries in the packet is 40.83 hours or more then, it exceeds for 5% of all packages.

ok

step-by-step explanation:

a

step-by-step explanation:

the answer is a