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?
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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.
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