Respuesta :
The appropriate test to perform is one sample t test
The rejection reason is t statistic less than -2.012 or t statistic more than -2.012
The p value of the test is 0.0292
Firstly,
As the population standard deviation is unknown and the sample size is more than 30, it is appropriate to use one sample t test for this hypothesis testing
Testing if the mean is changed from 700 levels or not
Null and alternate hypothesis are 700
Degree of freedom,
n-1
= 48-1
= 47
Using alpha level 0.05 and t critical table, we found the following two critical values
t critical values= -2.012 and 2.012
So, the rejection reason is t statistic less than -2.012 or t statistic more than -2.012
Now,
Population means = 700 hours
Sample mean = 675 hours
n = 48
So,
Test statistic= (mean-alternate hypothesis)/(s/√n)
= (675-700)/ (77/√48)
=-25/11.1140
= -2.249
Degree of freedom = n-1
= 48-1
= 47
With t distribution table for -2.249 and 47 degrees of freedom obtain p value of 0.0292
So, pvalue= 0.0292
Reject null hypothesis since the p value is less than alpha level
So, we conclude that the mean has changed from 700 hours
To know more about Population mean refer to:
http://brainly.com/question/29441200
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