The management of a health insurance company wants to know the percentage of its policyholders who have tried alternative treatments (such as acupuncture, herbal therapy, etc.). A random sample of 24 of the company's policyholders were asked whether or not they have ever tried such treatments.

The following are their responses.

Yes, No, No, Yes, No, Yes, No, No, No, Yes, No, No, Yes, No, Yes, No, No, No, Yes, No, No, No, Yes, No,

Round to 5 decimals.

(a) What is the point estimate of the corresponding population proportion?

(b) Construct a 99% confidence interval for the percentage of this company's policyholders who have tried alternative treatments.