Construct the confidence interval for the population mean .

c=0.90 ,x=7.1,=0.3,and n=41

Construct the confidence interval for the population mean .

c=0.90 ,x=15.4,=6.0 , and n=90

Find the minimum sample size n needed to estimate for the given values ofc, , and E. Assume that a preliminary sample has at least 30 members. c=0.98, =8.4, and E=1

People were polled on how many books they read the previous year. How many subjects are needed to estimate the number of books read the previous year within one book with 90% confidence? Initial survey results indicate that =14.1books.

A doctor wants to estimate the HDL cholesterol of all20- to29-year-old females. How many subjects are needed to estimate the HDL cholesterol within 4 points with 99% confidence assuming=18.9? Suppose the doctor would be content with 90% confidence. How does the decrease in confidence affect the sample sizerequired?

Construct the indicated confidence interval for the population mean using thet-distribution. c=0.95, x=12.6, s=4.0, n=6

Construct the indicated confidence interval for the population meanusing thet-distribution. c=0.80,x=110,s=10,n=7