How much does a sleeping bag cost? Let’s say you want a sleepingbag that should keep you warm in temperatures from20oF to 45oF. A random sampleof prices ($) for sleeping bags in this temperature range was takenfrom Backpacker Magazine: Gear Guide (Vol. 25, Issue 157, No.2.)
80Â Â Â Â Â 90Â Â Â Â Â Â Â 100Â Â Â Â Â 120Â Â Â Â Â 75Â Â Â Â Â 37Â Â Â Â Â 30Â Â Â Â Â Â Â 23Â Â Â Â Â Â Â 100Â Â Â Â Â 100
105Â Â Â Â Â 95Â Â Â Â Â Â Â 105Â Â Â Â Â 60Â Â Â Â Â 110Â Â Â Â Â 120Â Â Â Â Â 95Â Â Â Â Â Â Â 90Â Â Â Â Â Â Â 60Â Â Â Â Â Â Â 70
Find the mean x ( round to two decimals places)
Find the sample standard deviation  s   ( round to two decimals places)
Find a 90% confidence interval for the mean price µ of allsummer sleeping bags.
2. Over the past few months, an adult patient has been treatedfor tetany (severe muscle spasms.) This condition is associatedwith total calcium level below 6 mg/dl . Reference: Manual ofLaboratory and Diagnostics Tests by F. Fischbach). Recently, thepatient’s total calcium tests gave the following readings inmg/dl
9.3Â Â Â Â Â Â 8.8Â Â Â Â Â Â 10.1Â Â Â Â 8.9Â Â Â Â Â Â 9.4Â Â Â Â Â Â 9.8
10.0Â Â Â Â 9.9Â Â Â Â Â Â 11.2Â Â Â Â 12.1
Find the mean x     ( roundto two decimals places)
Find the sample standard deviation  s    (round to two decimals places)
Find a 99.9% confidence interval for the mean calcium level.
3.A random sample of 40 students taken from a university showedthat their mean GPA is 2.94 and the standard deviation of theirGPAs is .30. Construct a 99% confidence interval for the mean GPAof all students at this university.
4.According to a study done by Dr. Martha S. Linet and others,the mean duration of the most recent headache was 8.2 hours for asample of 5055 females 12 through 29. Make a 95% confidenceinterval for the mean duration of all headaches for all 12 to29-year-old females. The standard deviation for this sample is 2.4hours.
5. According to a survey conducted by USA TODAY, 73.2% of theworkers in the United States drive alone to work. Assume that thissurvey is based on a random sample of 1000 US workers.
Find a 95% confidence interval for all workers in the UnitedStates who drive alone to work.
