3. How much does a sleeping bag cost? Backpacker Magazine took a random sample of the cost of 31 sleeping bags that should keep you warm above 20"F and found that the mean cost was $ 119.75 with a standard deviation of $17.20. Use a calculator to build a 95% confidence interval for the population mean price of all of these types of sleeping bags. Then write a sentence or two to explain what your confidence interval means