For the first part, the results get quite crazy. I hardly believe that you're supposed to do this by hand, so I'm afraid that there's some typo in the question.
As for the second part, we have
Plug your value for x and you have
We can rewrite the quantity as
0.3333 as a fraction is 1/3
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Answer with explanation:</u></h2>
Formula to find the confidence interval for population mean :-
, where = sample mean.
t*= critical z-value
n= sample size.
s= sample standard deviation.
By considering the given question , we have
n= 50
Degree of freedom : df = 49 [ df=n-1]
Significance level :
Using students's t-distribution table, the critical t-value for 95% confidence =
Then, 95% confidence interval for the population mean will be :
Hence, a 95% confidence interval for the population mean = (24.24, 27.76)
Since 28 is not contained in the above confidence interval , it means it is not reasonable that the population mean is 28 weeks.
Answer:
d
Step-by-step explanation:
(7,1)