SOLUTION:
A battery company claims that its batteries last an average of 100 hours under normal use. After several complaints that the batteries do not last this long, an independent testi
Algebra.Com
Question 1101475:
A battery company claims that its batteries last an average of 100 hours under normal use. After several complaints that the batteries do not last this long, an independent testing laboratory decided to test the company’s claim with a random sample of 42 batteries. The data from the 42 batteries appeared to be unimodal and symmetric with a mean 97 hours and a standard deviation of 12 hours.
What sample size would allow us to increase our confidence level to 95% while reducing the margin of error to only 3 hours? Round up to the nearest whole number.
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
A battery company claims that its batteries last an average of 100 hours under normal use. After several complaints that the batteries do not last this long, an independent testing laboratory decided to test the company’s claim with a random sample of 42 batteries. The data from the 42 batteries appeared to be unimodal and symmetric with a mean 97 hours and a standard deviation of 12 hours.
What sample size would allow us to increase our confidence level to 95% while reducing the margin of error to only 3 hours? Round up to the nearest whole number.
Since E = z*s/sqrt(n), n = [z*s/E]^2
-----
n = [1.96*12/3]^2 = 62 when rounded up
-------------
Cheers,
Stan H.
-------------
RELATED QUESTIONS
A battery company claims that its batteries last an average of 100 hours under normal... (answered by stanbon)
The ABC battery company claims that their batteries last at least 100 hours, on average.... (answered by Boreal)
A phone maker claims that its phones’ batteries last for 13.7 hours on average with... (answered by Boreal)
The distribution of battery lives are assumed to be approximately normal and a... (answered by robertb)
The ABC battery company claims that their batteries last at least 100 hours, on average.... (answered by ewatrrr,ed42ptt)
Quick Start Company makes 12-volt car batteries. After many years of product testing, the (answered by ewatrrr)
Please help me with this question, I have submitted it several times to no avail.
An... (answered by macston)
The following problem concerns laptop computer batteries. As the computer runs, the total (answered by stanbon)
A smartphone manufacturer advertises that, on average, its cell phone batteries will last (answered by stanbon)