Problem#23. Confidence Interval for a Population Proportion

Use the retailer data provided in Problem#7. That includes a sample of 150 customer. Answer the following questions based on the data.

a) Compute the 95% confidence interval for the population proportion of customers who are 40 years or older. Interpret the confidence interval.

b) Compute the 99% confidence interval for the population proportion of customers who spent $150 or more. Interpret the confidence interval.

c) Compute the 90% confidence interval for the population proportion of customers who used their EStore Card for the transaction. Interpret the confidence interval.

Data #23