Answer:
The degrees of freedom are:
And the p value would be given by:
Since the p value is lower than the significance level we have enough evidence to reject the null hypothesis and we can conclude that the true deviation is different from 8 days.
Step-by-step explanation:
Data given
represent the sample size
represent the confidence level
represent the sample variance obtained
represent the value that we want to test
Hypothesis to test
We want to verify if the true deviation is equal to 8 days o not, so the system of hypothesis would be:
Null Hypothesis:
Alternative hypothesis:
The statistic is given by:
Replacing we got:
The degrees of freedom are:
And the p value would be given by:
Since the p value is lower than the significance level we have enough evidence to reject the null hypothesis and we can conclude that the true deviation is different from 8 days.