Answer Happy

A researcher wishes to estimate the average blood alcohol concentration (BAC) for drivers involved in fatal accidents who are found to have positive BAC values. He randomly selects records from 75 such drivers in 2009 and determines the sample mean BAC to be 0.16 g/dL with a standard deviation of 0.080 g/dL. Complete parts (a) through (d) below. (a) A histogram of blood alcohol concentrations in fatal accidents shows that BACs are highly skewed right Explain why a large sample size is needed to construct a confidence interval for the mean BAC of fatal crashes with a positive BAC A. Since the distribution of blood alcohol concentrations highly skewed right, a large sample size is necessary to ensure that the distribution of the sample mean is approximately normal. OB. Since the distribution of blood alcohol concentrations is highly skewed right, a large sample size is needed to minimize the margin of error to ensure only the peak of the sampling distribution is captured in the confidence interval. OC. Since the distribution of blood alcohol concentrations highly skewed right, a large sample size is needed to maximize the margin of error to ensure that both tails are accounted for in the confidence interval. OD. Since the distribution of blood alcohol concentrations highly skewed right, a large sample size is needed to ensure that it contains at least 5% of the population (b) Recently there were approximately 25,000 fatal crashes in which the driver had a positive BAC. Explain why this, along with the fact that the data were obtained using a simple random sample satisfies the requirements for constructing a confidence interval. O A. The sample size is likely less than 10% of the population. O B. The sample size is likely greater than 5% of the population. OC. The sample size is likely greater than 10% of the population OD. The sample size is likely less than 5% of the population. (c) Determine and interpret a 90% confidence interval for the mean BAC in fatal crashes in which the driver had a positive BAC. Select the correct choice below and fill in the answer boxes to complete your choice. (Use ascending order. Round to three decimal places as needed.) A. The researcher is % confident that the population mean BAC is between and for drivers involved in fatal accidents who have a positive BAC value O B. There is a % probability that the population mean BAC is between and for drivers involved in fatal accidents who have a positive BAC valus. OC. The researcher is % confident that the population mean BAC is not between and for drivers involved in fatal accidents who have a positive BAC value. (d) All areas of the country use a BAC of 0.08 g/dL as the legal intoxication level. Is it possible that the mean BAC of all drivers involved in fatal accidents who are found to have positive BAC values is less than the legal intoxication level? Explain O A. While the target value lies within the confidence interval, since it is less than the sample mean, it is unlikely that it is the true population mean O B. Not only is it possible that the population mean is not captured in the confidence interval, in this case, it is quite likely OC. Since the target value lies within the confidence interval, it is certainly a plausible value for the population mean OD. While it is possible that the population mean is not captured in the confidence interval, it is not likely