statistics
posted by Patrick .
The mean lifetime of a sample of 100 light tubes is 1570 hours with a standard deviation of 80 hours test the hypothesis that the mean lifetime of the tubes is 1600 hours

statistics 
PsyDAG
Z = (scoremean)/SEm
SEm = SD/√n
Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion/probability of the Z score.
Respond to this Question
Similar Questions

statistics
Solve the problem. The lifetime of a new brand of light bulb can be described by a Normal model with a mean of 2000 hours and a standard deviation of 250 hours. Find the percentage of light bulbs that will last more than 2600 hours. … 
STATISTICS HELP
The lifetime of a disk drive head is normally distributed with a population mean of 1000 hours and standard deviation of 120 hours. Determine the probability that the average lifetime for 9 disk drives will exceed 940 hours. Need to … 
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
Can anyone tell me how to use TI84 calculator to solve this problem? 
Statistics
A company has developed a new type of light bulb, and wants to estimate its mean lifetime. A simple random sample of 12 bulbs had a sample mean lifetime of 692 hours with a sample standard deviation of 30 hours. It is reasonable to … 
statics
The standard deviation of the lifetime of certain TV picture tubes is estimated as 150 hours. How much large a sample must be taken in order to be 99% confident that the error in the estimated means lifetime will not exceed 25 hours 
business statitics
a) The mean lifetime of a sample of 100 light tubes produced by a company is found to be 1570 hours with standard deviation of 80 hours. Test the hypothesis that the mean lifetime of the tubes produced by the company is 1600 hrs. (7 … 
statistics
A manufacturer claims that the mean lifetime of its lithium batteries is 1400 hours. A homeowner selects 25 of these batteries and finds the mean lifetime to be 1380 hours with a standard deviation of 80 hours. Test the manufacturers … 
Statistics (Math 210)
Hi there, I am doing my statistics homework and am having trouble with a few problems. I sincerely appreciate any help I receive! :) A manufacturer claims that the mean lifetime of its lithium batteries if 1200 hours. A homeowner selects …