8.4.6 . You are the operations manager for an airline and you are considering a higher fare level for passengers in aisle seats. How many randomly selected air passengers must you survey? Assume that you want to be 90% confident that the sample percentage is within 2.5 percentage points of the true population percentage. Complete parts (a) and (b) below. a. Assume that nothing is known about the percentage of passengers who prefer aisle seats. b. Assume that a prior survey suggests that about 38% of air passengers prefer an aisle seat. The heights of 25 random palm trees in the city are measured. The mean is computed to be 20.1ft and variance is 19.8. Construct the 95% confidence interval for 62. A genetic experiment with peas resulted in one sample of offspring that consisted of 423 green peas and 160 yellow peas. Construct a 90% confidence interval to estimate of the percentage of yellow peas. Consider a drug that is used to help prevent blood clots in certain patients. In clinical trials, among 5838 patients treated with this drug, 148 developed the adverse reaction of nausea. Use a 0.05 significance level to test the claim that 3% of users develop nausea. Does nausea appear to be a problematic adverse reaction? (Use the critical values method) In a test of the effectiveness of garlic for lowering cholesterol, 81 subjects were treated with raw garlic. Cholesterol levels were measured before and after the treatment. The changes (before minus after) in their levels of LDL cholesterol (in mg/dL) have a mean of 0.4 and a stande deviation of 2.14. Use a 0.01 significance level to test the claim that with garlic treatment, the mean change in LDL cholesterol is greater than 0. What do the results suggest about the effectiveness of the garlic treau'nent? Assume that a simple random sample has been selected. Identify the null and alternative hypotheses, test statistic, and state the final conclusion that addresses the original claim. (Use the critical values method) Rhino viruses typically cause common colds. In a test of the effectiveness of echinacea, 35 of the 41 subjects treated with echinacea developed rhinovirus infections. In a placebo group, 91 of the 104 subjects developed rhinovirus infections. Use a 0.05 significance level to test the claim that echinacea has an effect on rhinovirus infections. (Use the critical value method) 7. A food safety guideline is that the mercury in fish should be below 1 part per million (ppm). Listed below are the amounts of mercury (ppm) found in tuna sushi sampled at different stores in a major city. Construct a 99% confidence interval estimate of the mean amount of mercury in the population. Does it appear that there is too much mercury in tuna sushi? 0.58 0.70 0.10 0.89 1.37 0.56 8. Listed in the data table are IQ scores for a random sample of subjects with medium lead levels in their blood. Also listed are statistics from a study done of IQ scores for a random sample of subjects with high lead levels. Assume that the two samples are independent simple random samples selected from normally distributed populations. Do not assume that the population standard deviations are equal. Construct a 99% confidence interval for \"medium um, and interpret the result. Medium lead level: 72 83 92 85 86 97 83 92 102 111 91 High lead level: n2=11 $289821 52:10.447 9. Several students were tested for reaction times (in thousandths of a second) using their right and left hands. (Each value is the elapsed time between the release of a strip of paper and the instant that it is caught by the subject.) Results from five of the students are included in the graph to the right. Use a 0.01 significance level to test the claim that there is no difference between the reaction times of the right and left hands. (Use critical value method) Righthand: 124 114 154 168 197 Lefthand: 129 151 177 199 218 10. Erica claims that college women have more credit card debt than college men. She took a random sample of 38 college men and 32 college women, and computed the following statistics: Men Women X1 =435 X2 = 781 51: 1026 52: 1489 Test the claim that college women have more credit card debt than college men at the 0.05 level of significance, using the critical value method. 11. An environmental engineer was asked to determine if carpeted rooms have more bacteria than non-carpeted rooms. She designed, experimented and collected data from 8 carpeted rooms and 8 non-carpeted rooms. Carpeted room 11.9 10.4 12.7 12.6 9.9 13.2 11.1 9.6 Non-carpeted room 7.1 11.1 7.9 9.4 6 10.3 8.6 12.3 Test the claim that the carpeted room has more bacteria than the non-carpeted room at the 0.01 level of significance, using the critical value method