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)

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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