Name: Challenge #3 1. A simple random sample of 50 adults Is obtained and each person's red blood cell count is measured (in microliters). The sample mean is 4.23. The population standard deviation for red blood cell counts is .40. Construct a 99% confidence interval estimate of the mean red blood cell count of adults. 2. What percentage of a normal distribution is within 2 standard deviations of the mean? (Select the closest answer.) a. b. c. d. 50% 95% 75% 100% 3. The area under the standard normal distribution between -2.0 and 1.35 is a. 0.3887 b. -.0658 c. 0.4332 d. .8887 4. A real estate agent records the ages of 50 randomly selected home buyers in her sales area. The mean age is 42 years, with a sample standard deviation of 8 years. a. Find a 99% confidence interval for the population mean age. 5. A simple random sample of 125 SAT scores has a mean of 1505. Assume that SAT scores have a standard deviation of 300. Construct a 95% confidence interval estimate of the mean SAT score