SOLUTION: The Pizza Shop wanted to determine what proportion of its customers ordered only cheese pizza. Out of 80 customers surveyed, 15 ordered cheese pizza. What is the 99% confidence int

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Question 1040401: The Pizza Shop wanted to determine what proportion of its customers ordered only cheese pizza. Out of 80 customers surveyed, 15 ordered cheese pizza. What is the 99% confidence interval of the true proportion of customers who order only cheese pizza?
A. 0.115 < p < 0.260
B. 0.086 < p < 0.289
C. 0.075 < p < 0.300
D. 0.102 < p < 0.273

Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
1 sample proportion
p=15/80=0.1875
CI interval +/- is z(0.995) sqrt{p(1-p)/n}
2.576*sqrt{(0.1875)(0.8125)/80}; the second term is 0.0436
multiplied by 2.576 is 0.1124
CI is (0.0751,0.2999)
It is C.