In 2000, the mean number of persons per household in Cecil County was 2.71. You would like to see if that figure has changed so you decide to construct a confidence interval. You believe that this variable is not normally distributed, so you take a random sample of n = 50 households in the county. The sample had a mean of Construct a 95% confidence interval for the population mean, following the directions below. Assume the population standard deviation is .
_______________________(a) What is the likely shape of the distribution of this variable, skewed left or skewed right (2 points)?
_______________________(b) What is the formula for E, the margin of error (2 points)?
_______________________(c) What is the value of for your interval (2 points)?
_______________________ (d) What is the value of the margin of error for your interval (2 points).
_______________________ (e) Give the 95% confidence interval (2 points).
please help im not sure about letter a nor b
Nov 22nd 2008, 05:35 PM
margin of error
your margin of error is the right side of the confidence interval formula. i.e. (either your t or z critical value times s/√n).