Question: A random sample of 365 medical doctors showed that 132 had a solo practice. Find a 90% confidence interval for the true proportion of all medical doctors who have a solo practice.

a) Find p-hat the point estimate for the true proportion (round to 2 decimal places)

b) Now, calculate confidence interval (you may use your calculator)

c) What would the margin of error be for this problem

d) Write an interpretive sentence for the interval found above

e) Find the sample size necessary for a 99% confidence level with a maximum error of estimate E = 2%., using the value of p-hat that you calculated above for the preliminary estimate of p.

f) Find the sample size necessary for a 99% confidence level with a maximum error of estimate E = 2%., when there is no initial estimate of p.