To calculate the confidence interval, we can use the formula for a proportion:
CI = p̂ ± Z * sqrt((p̂(1-p̂)/n))
where p̂ is the sample proportion, Z is the z-score corresponding to the desired confidence level, and n is the sample size.
In this case, the sample proportion (p̂) is 15/80 = 0.1875.
The z-score for a 99% confidence level is approximately 2.576 (taken from a standard normal distribution table).
Plugging in the values, we get:
CI = 0.1875 ± 2.576 * sqrt((0.1875 * (1-0.1875)/80))
= 0.1875 ± 0.0497
= (0.1378, 0.2372)
Therefore, the 99% confidence interval of the true proportion of customers who order only cheese pizza is (0.138, 0.237).
The Pizza Shop wanted to determine what proportion of its customers ordered only cheese pizza. Out of 80 customers surveyed, 15 ordered cheese pizza. They want a 99% confidence interval of the true proportion of customers who order only cheese pizza.
What is the 99% confidence interval of the true proportion of customers who order only cheese pizza?
Question 26 options:
(0.075, 0.300)
(0.115, 0.260)
(0.086, 0.289)
(0.102, 0.273)
1 answer
1 answer