Question

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 95​% ​confidence? Initial survey results indicate that sigmaequals19.4 books. A 95 % confidence level requires nothing subjects.

2.Find the critical values chi squared Subscript Upper L and chi squared Subscript Upper R for the given confidence level c and sample size n. cequals0.95​, nequals24

3.Use technology to construct the confidence intervals for the population variance sigmasquared and the population standard deviation sigma. Assume the sample is taken from a normally distributed population. cequals0.99​, sequals37​, nequals19

4.A doctor wants to estimate the HDL cholesterol of all​ 20- to​ 29-year-old females. How many subjects are needed to estimate the HDL cholesterol within 3 points with 99 % confidence assuming sigma equals 19.2 question mark Suppose the doctor would be content with 90 % confidence. How does the decrease in confidence affect the sample size​ required?

Answer 1

https://drive.google.com/open?id=1miDykB956rSHGgAYD93YaJKxmD9a_oZ1

A 90% confidence level requires

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https://drive.google.com/open?id=1miDykB956rSHGgAYD93YaJKxmD9a_oZ1

A 99% confidence level requires

A 90% confidence level requires