Calculator Homework #6 - Confidence Intervals (Mean and Proportion) Use the calculator to determine the confidence intervals for the following.

Exercise 1 A random sample of 49 shoppers showed that they spend an average of $23.45 per visit at Barnes and Nobles Book store. The standard deviation of the population is $2.80. Find the 90% confidence interval of the true mean.

Exercise 2 The daily salaries of substitute teachers for 8 local school districts are shown below. Find the 95% confidence interval for the mean of the salaries. $60 $56 $60 $55 $70 $55 $60 $55

Exercise 3 An employment counselor found that in a sample of 100 unemployed workers, 65% were not interested in returning to work. Find the 95% confidence interval of the true proportion of workers who do not wish to return to work.