Normal (or average) body temperature of humans is often thought to be 98.6°F. Is that number really the average? To test this, we will use a data set obtained from 67 healthy female volunteers aged 18 to 40 who were participating in vaccine trials. We will assume this sample is representative of a population of all healthy females. The mean body temperature for the 67 females in our sample is 98.85°F and the standard deviation is 0.852°F. The data are not strongly skewed. Use the Theory-Based Inference applet to find a 95% confidence interval for the population mean body temperature for healthy females. Round your answers to 2 decimal places, e.g. 0.75. The confidence interval is [Enter your answer; confidence interval, lower bound] to [Enter your answer; confidence interval, upper bound].
Most dermatologists recommend using sunscreens that have a Sun Protection Factor (SPF) of at least 30. One of the authors wanted to find out whether the SPF of sunscreens used by students at her school exceeds this value on average. To collect data, the author surveyed students in her introductory statistics course and found that in a sample of 49 students, the mean SPF was 33.62 and the standard deviation of SPF was 18.26. The data were not strongly skewed. Use the Theory-Based Inference applet to find and report the 95% confidence interval for the parameter of interest. Round answers to 4 decimal places, e.g. 0.7523. We are 95% confident that the mean SPF level of sunscreen used by all Cal Poly students is between [Enter your answer; lower bound] and [Enter your answer; upper bound].