SOLUTION: Andy is a restaurant owner. He believes 80% of his customers are satisfied with the food quality of his restaurant. From a random sample of 81 customers, what are the following pro

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Question 1186554: Andy is a restaurant owner. He believes 80% of his customers are satisfied with the food quality of his restaurant. From a random sample of 81 customers, what are the following probabilities? (Round your answers to four decimal places, if needed.)
(c) What is the probability that the sample proportion of customers who are satisfied with the food quality is between 78% and 85%?

Answer by robertb(5830) About Me  (Show Source):
You can put this solution on YOUR website!
The lower z-value is computed as follows: .
The upper z-value is computed as follows: .

Thus,