SOLUTION: A manufacturer claims that the mean lifetime, M, of its light bulbs is 52 month. The standard deviation of these lifetimes is 5 months. Eighty bulbs are selected at random, and the
Algebra.Com
Question 449396: A manufacturer claims that the mean lifetime, M, of its light bulbs is 52 month. The standard deviation of these lifetimes is 5 months. Eighty bulbs are selected at random, and their mean lifetime is found to be 51 months. Can we conclude, at the 0.05 level of significance, that the mean lifetime of light bulbs made by this manufacturer differs from 52 months?
Perform a two-tailed test.
I am having a lot of trouble with this. Can someone hep me?
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
A manufacturer claims that the mean lifetime, M, of its light bulbs is 52 months. The standard deviation of these lifetimes is 5 months.
-----------------------------
Eighty bulbs are selected at random, and their mean lifetime is found to be 51 months.
---------
Can we conclude, at the 0.05 level of significance, that the mean lifetime of light bulbs made by this manufacturer differs from 52 months?
Perform a two-tailed test.
---
Ho: u = 52 months
Ha: u is not 52 months (claim)
-----------------------------
x-bar = 51 months
---
t(51) = (51-52)/[5/sqrt(80)] = -1.7889
----
p-value = 2*P(t < -1.7889 when df = 79) = 2*tcdf(-100,-1.7889,79) = 0.0775
-----
Since the p-value is greater than 5%, fail to reject Ho.
The test results do not support the claim.
==============================================
Cheers,
Stan H.
==============================================
RELATED QUESTIONS
A manufacturer claims that the mean lifetime, u of its light bulbs is 43 months. the... (answered by Boreal)
A manufacturer claims that the mean lifetime, , of its light bulbs is months. The... (answered by stanbon)
Please help me with this statistical problem.
A manufacturer claims that the mean... (answered by stanbon)
A manufacturer claims that the mean lifetime, , of its light bulbs is months. The... (answered by stanbon)
A manufacturer claims that the mean lifetime,
μ
, of its light bulbs is
45... (answered by ikleyn)
A manufacturer claims that the mean lifetime, , of its light bulbs is months. The... (answered by stanbon)
A manufacturer claims that the mean lifetime,u , of its light bulbs is 51 months. The... (answered by stanbon)
a manufacturer of light bulbs claims that its new light bulb has a mean life of 1000... (answered by stanbon)
a manufacturer of light bulbs claims that its new light bulb has a mean life of 1,000... (answered by Fombitz)