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Answer: A. (636.9, 653.1)
Step-by-step explanation:
Given : Sample size : n=56
Significance level :
Critical value :
Sample mean : 
Standard deviation : 
The 95% confidence interval for population mean is given by :-

Hence, 95% confidence interval for population mean is (636.9, 653.1).
Answer:
They would need to sell more than or equal to 140 boxes of cookies.
Step-by-step explanation:
The equation would be
2.50t >= 350
-------- -------
2.50 2.50
t >= 140