SOLUTION: The mean life of a battery used in a digital clock is 305 days. The lives of the batteries follow a normal distribution. The battery was recently modified to last longer. A sample

Question 1169693: The mean life of a battery used in a digital clock is 305 days. The lives of the batteries follow a normal distribution. The battery was recently modified to last longer. A sample of 30 of the modified batteries had a mean life of 311 days with a variance of 144 days. A hypothesis test isundertaken to determine whether the modification increased the battery life. The p - value of the test is equal to
Answer by Boreal(15235) (Show Source): You can put this solution on YOUR website!
this is a t-test
t(df=29)=(x bar-mean/)s/ sqrt(n); s is sqrt of variance or 12.
=6*sqrt(30)/12
2.738
One-way test
p-value is 0.005

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