A manufacturer of photographic flash batteries took a sample of 13 batteries from the production of...

A manufacturer of photographic flash batteries took a sample of 13 batteries from the production of any given day and used them continuously until they were used up. Battery life in hours until it ran out was: 342, 426, 317, 545, 264, 451, 749, 631, 512, 266, 492, 562 and 298. With a significance level of 0.05, there is evidence that the Battery life is more than 400 hours? (assume that life times have normal distribution)

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Expert Solution

Null hypothesis

Alternative hypothesis

We have for given sample,
Population mean for given sample=400
Sample mean=450.385
Sample standard deviation s=150.23
Sample size =n=   13

Degree of freedom = n-1 =12



t test statistic formula is

=1.21

P value = 0.1248..................by using Excel command =TDIST(1.21,12,1)

P value is =0.1248 > 0.05

Therefore, We fail to reject H0 at

orchestra answered 2 years ago

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