1. Warm Up
Crew members and passengers on overseas flights are exposed to elevated levels of cosmic ray radiation. A 2002 paper reported a mean radiation dose of 219 mrems for a random sample of 100 passengers flying ANA Airlines from Japan to the US. Assume the standard deviation of the radiation dose for all passengers on ANA is 35 mrems. Construct a 95% confidence interval for the value of m, the mean radiation dose received by all passengers on ANA flights from Japan to the US. (Remember to check the conditions!)

2. Warm Up - Continued
Which of the following statements concerning the confidence interval we calculated is (are) true? a) 95% of all samples will have a sample mean between 212 and 226 mrems. b) 95% of all confidence intervals constructed in a similar manner will capture the true population mean. c) 95% of the time the true population mean radiation dosage is between 212 and 226 mrems. d) 95% of the passenger radiation dosage levels are between 212 and 226 mrems.

3. Example
Assume that a random sample of 500 Californians found that 296 said they are not conserving as much water since the drought ended. Construct a 90% confidence interval for the proportion of all Californians who are not conserving as much water since the drought ended. (We will assume conditions for the confidence interval are met)

4. Practice
A 2004 research paper found that in a random sample of 6212 American children 1720 of them ate fast food on a typical day. Based on this paper, construct a 99% confidence interval for the proportion of all American children who eat fast food on a typical day. (Assume conditions for the confidence interval are met)

5. Practice
A 2009 survey of 2667 hiring managers reported by CareerBuilder.com found that 1214 indicated they had used social networking sites such as Facebook to research job applicants. Assume that the sample is representative of all hiring managers in the US. Construct and interpret a 95% confidence interval for the proportion of hiring managers that use social networking sites to research job applicants.

6. Practice
A 2009 survey of 2667 hiring managers reported by CareerBuilder.com found that 1214 indicated they had used social networking sites such as Facebook to research job applicants. Assume that the sample is representative of all hiring managers in the US. Construct a 92% confidence interval by hand. Assume conditions are met.