Answer:
The 95% confidence interval for the percent of all coffee drinkers who would say they are addicted to coffee is between 21% and 31%.
Step-by-step explanation:
In a sample with a number n of people surveyed with a probability of a success of , and a confidence level of
, we have the following confidence interval of proportions.
In which
z is the zscore that has a pvalue of .
The margin of error is:
A confidence interval has two bounds, the lower and the upper
Lower bound:
Upper bound:
In this problem, we have that:
Lower bound:
Upper bound:
The 95% confidence interval for the percent of all coffee drinkers who would say they are addicted to coffee is between 21% and 31%.