SOLUTION: Please Please PLease help me with this! The operations manager at a light bulb factory wants to determine whether there is any difference in the mean life expectancy of bulbs ma

Question 21655: Please Please PLease help me with this!
The operations manager at a light bulb factory wants to determine whether there is any difference in the mean life expectancy of bulbs manufactured on two different types of machines. The population standard deviation of machine I is 110 hours and of machine II is 125 hours. A random sample of 24 light bulbs from machine I indicates a sample mean of 375 hours and a similar sample of 25 bulbs from machine II indicates a sample mean of 362 hours.
a) Using a 0.05 level of significance, is there any evidence of a difference in the mean life of bulbs produced by the two types of machines?

Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
The operations manager at a light bulb factory wants to determine whether there is any difference in the mean life expectancy of bulbs manufactured on two different types of machines. The population standard deviation of machine I is 110 hours and of machine II is 125 hours. A random sample of 24 light bulbs from machine I indicates a sample mean of 375 hours and a similar sample of 25 bulbs from machine II indicates a sample mean of 362 hours.
a) Using a 0.05 level of significance, is there any evidence of a difference in the mean life of bulbs produced by the two types of machines?
----------
Ho: mu1-mu2=0
Ha: mu1-mu2 is not 0
This is a two tail test of difference of means
x1-bar=375;s1=110;n1=24
m2-bar=362;s2=125;n2=25
Find the t-value of (375-362)=0.3869
Find the associated p-value=0.70
Since p-value > alpha=0.05, Fail to reject Ho.
Conclusion: There is no difference in the mean life of bulbs produced
by the two types of machines.
Cheers,
Stan H.
RELATED QUESTIONS
Could you please help me with this problem? The intensity (I) of light from a light... (answered by scott8148)

The quality-control manager at a light bulb factory needs to determine whether the mean... (answered by Boreal)

a manufacturer knows that in a box of 120 light bulbs there will be 3 defective bulbs.... (answered by KMST)

A quality engineer in a light bulb factory is planning a study to estimate the average... (answered by stanbon)

Hi I really need help answering couple of questions, please could someone explain them to (answered by khwang)

Hello, I need help with this question One light bulb is selected at random from a lot... (answered by math_helper)

Can you help me with this? a store manager decides to market 40 combinations of light... (answered by stanbon)

If a quality control manager wants to estimate the average life of light bulbs to within... (answered by ikleyn)

Hello I submitted this problem earlier but, I put the wrong e-mail. Could I please have... (answered by josmiceli)