SOLUTION: A manufacturer of a certain brand of wristwatch claims that the mean life expectancy of the battery of the watch is 48 months. A researcher wants to validate this claim so he chose

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Question 1179067: A manufacturer of a certain brand of wristwatch claims that the mean life expectancy of the battery of the watch is 48 months. A researcher wants to validate this claim so he chose a sample of 64 watches and noted that their mean life expectancy is 45 months with a standard deviation of two months. At α = 0.05, can you conclude that the mean life expectancy is less than 48 months? Prove your answer.
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!

Hi
population: µ  = 48mo    Sample(n=64): µ  = 45mo  and s = 2mo
Ho:  µ  = 48
Ha:  µ  < 48
Confidence Interval .05:  one-tailed t-test: t(df63) = |t-value|> 1.6694 Reject Ho

t-value = blue+%28-3%29%2Fblue%282%2F8%29 = -12
|-12| > 1.6694 
Reject Ho, Evidence shows mean life expectancy is < 48 months

Wish You the Best in your Studies.