4/7/2017 Print Test PRINTABLE VERSION Practice Test 2 Question 1 Suppose that the length X of the life (in years) of a battery for a computer has a distribution that can be described by the pdf: x2 x 242 f(x) = e 121 Determine the probability that the battery fails before the one year warranty expires on the computer. a) 0.1082 b) 0.2041 c) 0.9959 d) 0.0082 e) 0.0041 f) None of the above Question 2 Let X be the amount of time (in hours) the wait is to get a table at a restaurant. Suppose the cdf is represented by 0 x<0 2 x f (x) = 0x7 49 1>7 7 Use the cdf to determine P(X 2). a) 0.2500 b) 0.3917 c) 0.2917 d) 0.7500 e) 0.4500 f) None of the above Question 3 https://assessment.casa.uh.edu/Assessment/PrintTest.htm 1/5 4/7/2017 Print Test Suppose the time a child spends waiting at for the bus as a school bus stop is exponentially distributed with mean 7 minutes. Determine the probability that the child must wait between 5 and 8 minutes on the bus on a given morning. a) 0.3294 b) 0.1706 c) 0.8294 d) 0.4895 e) 0.3706 f) None of the above Question 4 Costs for standard veterinary services at a local animal hospital follow a Normal distribution with a mean of $79 and a standard deviation of $20. What is the probability that one bill for veterinary services costs between $55 and $103? a) 0.3849 b) 0.5000 c) 0.6151 d) 0.7699 e) 0.2301 f) None of the above Question 5 If x is normally distributed with a mean of 30 and a standard deviation of 10, find P(30 x 47). a) 0.455 b) 0.955 c) 0.655 d) 0.755 e) 0.855 f) None of the above https://assessment.casa.uh.edu/Assessment/PrintTest.htm 2/5 4/7/2017 Print Test Question 6 Find a value of c so that P(Z c) = 0.71. a) 0.75 b) 0.55 c) 1.55 d) 0.55 e) 1.11 f) None of the above Question 7 Current research indicates that the distribution of the life expectancies of a certain protozoan is normal with a mean of 50 days and a standard deviation of 10.5 days. Find the probability that a simple random sample of 36 protozoa will have a mean life expectancy of 53 or more days. a) 0.6125 b) 0.0865 c) 0.2432 d) 0.9568 e) 0.0432 f) None of the above Question 8 In a large population, 67% of the households have cable tv. A simple random sample of 100 households is to be contacted and the sample proportion computed. What is the probability that the sampling distribution of sample porportions is less than 76%? a) 0.8642 b) 0.1358 c) 0.4861 d) 0.9722 e) 0.0278 https://assessment.casa.uh.edu/Assessment/PrintTest.htm 3/5 4/7/2017 f) Print Test None of the above Question 9 If the 90% confidence limits for the population mean are 36 and 44, which of the following could be the 97% confidence limits a) (36, 41) b) (39, 41) c) (35, 45) d) (39, 43) e) (38, 45) f) None of the above Question 10 An SRS of 24 students at UH gave an average height of 5.9 feet and a standard deviation of .1 feet. Construct a 90% confidence interval for the mean height of students at UH. a) (4.650, 7.350) b) (5.893, 5.907) c) (5.865, 5.935) d) (4.400, 7.700) e) (5.729, 6.071) f) None of the above Question 11 Failing to reject a false null hypothesis is classified as a a) Type I error b) Type II error c) Power Question 12 Let x represent the hemoglobin count (HC) in grams per 100 milliliters of whole blood. The distribution for HC is approximately normal with = 14 for healthy adult women. Suppose that a female patient has taken https://assessment.casa.uh.edu/Assessment/PrintTest.htm 4/5 4/7/2017 Print Test 12 laboratory blood samples in the last year. The HC data sent to her doctor is listed below. We would like to know if the data indicates this patient has significantly high HC compared to the population. 16, 21, 20, 22, 14, 19, 19, 15, 17, 19, 20, 17 Give the pvalue and interpret the results. a) p = 0.0000 Based on 5% significance level, I will fail to reject the null hypothesis and conclude this patient does not have a high HC level. b) p = .0562 Based on 5% significance level, I will fail to reject the null hypothesis and conclude this patient does not have a high HC level. c) p = 0.0000 Based on 5% significance level, I will reject the null hypothesis and conclude this patient has a high HC level. d) p = .1053 Based on 5% significance level, I will fail to reject the null hypothesis and conclude this patient does not have a high HC level. e) p = 0.0001 Based on 5% significance level, I will reject the null hypothesis and conclude this patient has a high HC level. https://assessment.casa.uh.edu/Assessment/PrintTest.htm 5/5