2. A sample of 16 weeks’ worth of sales shows mean sales of 100 units. Assume...
2. A sample of 16 weeks’ worth of sales shows mean sales of 100 units. Assume the population standard deviation is 16 units. Construct a 95% confidence interval for the weekly number of units sold.
Homework Answers
Answer
We will use z distribution in this case because we know that when the population standard deviation known, we use z distribution.
So, the formula confidence interval is given as
where 
sigma is standard deviation and n is sample size
z score for 95% confidence interval is 1.96 (using z distribution table)
setting the given values in the above formula
we get
this gives us
CI = (100-7.84, 100+7.84) = (92.16,107.84)
So, the required 95% confidence interval is (92.16,107.84)
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