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QUESTION 4 You measure the lifetime of a random sample of 25 rats that are exposed to 10 Sv of radiation (the equivalent of 1000 REM) for which the LD 100 is 14 days. The sample mean is ]= 13.8 days. Suppose that the lifetimes for this level of exposure follow a Normal distribution with unknown mean / and standard deviation o = 0.75 days. A 95% confidence interval for u is 13.45 to 14.15. 13.51 to 14.09. 13.55 to 14.05. 13.74 to 13.86. QUESTION 5 A 95% confidence interval for the true mean cholesterol of adult males based on 25 randomly selected subjects extends from 175 mg/L to 250 mg/L. A proper interpretation of the confidence interval would be that 95% of the population has a cholesterol level between 175 and 250 mg/L. we are 95% confident that the true mean cholesterol level of the population falls between 175 and 250 mg/L. there is a 95% chance that a randomly selected individual has a cholesterol level that falls between 175 and 250 mg/L. "in repeated samples of size 25, the sample mean will fall between 175 and 250 mg/L 95% of the time. QUESTION 6 Suppose we are testing the null hypothesis Ho : / = 20 and the alternative Ho : / - 20 for a Normal population with o= 6. A random sample of nine observations is drawn from the population, and we find the sample mean of these observations is > = 17. The P-value is closest to 0.0668. 0. 1336. 0.0332. 0.3085. QUESTION 7 The average amount spent on health care by U.S. citizens over age 18 is speculated to be $1250 per year. A special interest group claims that this amount is inaccurate and hires an independent third party to investigate the claim. The appropriate null and alternative hypotheses, Ho and Ha, for y are Ho : H = 1250 and Ha : H = 1250. Ho : M 2 1250 and Ha : H 1250. cannot be specified without knowing the size of the sample used