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STATS 50 MCQs Quiz




Question;1. Experts have estimated that 25% of all homeless people in the U.S. are veterans.The proportion of Americans in general who are homeless is 0.11. For random samples of 100 people, which is more normal?A) distribution of sample proportion, when the population proportion is 0.11B) distribution of sample proportion, when the population proportion is 0.25C) both the same2. Many biologists and anthropologists claim that 10 percent of all children conceived in the context of a marriage outside the couple.In this situation, the standard deviation for samples of 225 births is 0.02. If the sample size would beA) smallerB) largerC) the same3. The shape of the distribution of sample proportion is approximately normal. If the sample size were decreaseA) less normalB) more normalC) the same4. The probability of birth by Caesarean in the U.S. is 0.30.If the probability of Caesarean birth is 0.30, and 140 which of these numbers is X?A) 0.30B) 140C) 500D)1405005. The probability of being a smoker for a population of college students is 0.20.The standard deviation for same deviation would be smallest for which of these sample sizes?A) 16B) 160C) 16,0006. The shape of the distribution of sample proportion is approximately normal. The shape would be least normal for which of these sample sizes?A) 16B) 160C) 16,0007. Suppose 300 in a sample of 1600 students smoke, whereas the population proportion smoking is 0.20. What n 300 1600A) nB) pC) p?D) X8. The standard deviation for samples of 1600 students is 0.01. The standard deviation would be smallest for whA) 16B) 160C) 16,0009. This graph shows the distribution of ACT scores for a population of students. Which of these is your best guess for the probability of a score being greater than 30?A) 0.016B) 0.036C) 0.16D) 0.3610. Lengths of newborn babies (in inches) have a mean of 20 and a standard deviation of 2. Once z-scores are found, this sketch of the tails of the normal curve can be used to estimate probabilities.A newborn with a length of 20 inches isA) not at all unusualB) somewhat unusualC) extremely unusual11. Pre-pregnancy BMI for a population of women is approximately normal with a mean of 24 and a standard de z curve to estimate the probability of a BMI below 17:Use the sketch of the tails of the z curve to estimate the probability of a BMI below 17:between:A) 0 and 0.005B) 0.005 and 0.01C) 0.01 and 0.025D) 0.025 and 0.05E) 0.05 and 112. Probabilities of scores on a 10-point quiz for a group of students are shown below.Score456780.Probability0.060.120.300.3004910.140Which of these is the median score?A) 7B) 7.5C) 813. Lifespans of male mice have a mean of 860 days and a standard deviation of 40 days. The shape of the distribution is moderately skewed to the left.If we take a sample of mice from this population, how do we denote the mean of their lifespansA) sB)?C) x?D)?E) p?F) pG) n14. In 1999, salaries of physician?s assistants in the U.S. had a mean of 68.0 thousand and a standard deviation of may have some skewness.In this problem, the number 17 is:A) a parameter denoted sB) a parameter denoted?C) a statistic denoted sD) a statistic denoted?15. Year-level for a population of undergraduate introductory statistics students had probability distribution show standard deviation was 1.0.Year1234Probability0. distribution isA) left-skewedB) right-skewedC) symmetric but not normalD) approximately normal16. The proportion of Americans over the age of five who speak another language besides English at home is 0.2 Americans over the age of five.Which one of these do we check in order to justify our claim for the mean of tA) Check that there is no bias in the sampling or study design.B) Check that the population is at least 10 times the sample size.C) Check that there are should be at least 10 in and out of the category of interest (speaking another language17. Online interviews of 1500 parents with children under the age of eight found the proportion who read to their 0.78. Suppose a reporter would like to claim that more than three-fourths (0.75) of all parents with children u minutes daily.What notation do we use for the number 0.75?A) pB) p?C)p018. Based on the data provided, can the reporter conclude that more than 0.75 of all parents with children under e daily?A) yesB) no19. The national rate of binge drinking among eighth graders is assumed to be 0.10. We would like to see if the ra a particular state differs significantly from the national rate. In a survey of 4000 eighth graders from that state in the previous month was 0.07.The size of the z-statistic isA) extremeB) not extremeC) borderline20. A Type I Error is rejecting the null hypothesis, even though it is true, a Type II Error is failing to reject the nuA) a Type I ErrorB) a Type II ErrorC) both (a) and (b)D) neither (a) nor (b)21. Recently a sample of 250 taxicab drivers in Massachusetts were observed, 17 of them were using seatbelts.How could we obtain a narrower interval?A) use a lower level of confidenceB) use a smaller sampleC) both (a) and (b)D) neither (a) nor (b)22. Which of the following would invalidate our confidence interval and subsequent conclusions?A) If the 600 sampled youths were not representative of all youths in terms of their vision.B) If the 600 sampled youths did not respond accurately to the question about vision impairment.C) Both (a) and (b).D) Neither (a) nor (b).23. In a 2006 poll of 1000 Americans, the proportion who were satisfied with the way things were going in the Uby X in this situation?A) 0.27B) 270C) 1000D) none of the above24.Each student in a class of 80 rolls 8 dice in order to perform inference about the mean of all dice rolls (whichhis or her sample to test the true null hypothesis that the population mean is 3.5 against the two-sided alternatreject at the? = 0.05 level?A) 0B) 4C) 8D) 28E) 52F) 72G) 76H) 8025.Suppose that 6 minutes had been the sample standard deviation. Use the fact that the t multiplier for 35 degreconsider a confidence interval for the population mean REM sleep time. Compared to the z interval, the t inteA) much widerB) slightly widerC) slightly narrowerD) much narrower26.For this problem, we will assume that the null hypothesis should be rejected as long as the P-value is less thanfor 8 degrees of freedom to the left of -2.896 is 0.01.) Suppose the mean and standard deviation for number oundergrads are used to test whether the mean credits taken by all undergrads is less than 15. Choose the correcircumstances. The mean and standard deviation are obtained from a representative sample of 9 undergrads, tThe mean and standard deviation are obtained from a representative sample of 9 undergrads, the data set hasA) Use a z procedure: the P-value is small if z): T-Value = XXXX P-Value = 0.04 DF = 30This was aA) paired studyB) two-sample study31.If we test to see if overall reaction times were longer for the cell phone group, and use = 0.01 as the cutoff forhypothesis and conclude the difference between means is greater than zero?A) yesB) no32.A survey for business owners, conducted on a sample of 8 countries, looked at the percentage of businesses inand the percentage that imported goods from China. Output is shown from carrying out a comparison with soNMeanStDevSE MeanExports825.6314.405.09Imports815.759.513.36Difference89.8812.914.5695% CI for mean difference: (-0.93, 20.68)T-Test of mean difference = 0 (vs not = 0): T-Value = 2.16 P-Value = 0.067This was aA) paired studyB) two-sample study33. Percentages of roads classified as bad in 2006 were compared for a sample of 11 northern cities and a sampleLocationNMeanStDevSE Meannorth1162.212.13.7south449.017.88.9Difference = mu (n) - mu (s)Estimate for difference: 13.1295% lower bound for difference: ?7.33T-Test of difference = 0 (vs >): T-Value = 1.37 P-Value = 0.12 DF = 4Considering the size of the P-value for the two-sided alternative, would a 95% confidence interval for the diffzero? (No calculations necessary.)A) Yes, definitely.B) No, not even close.C) Borderline: either just barely or not quite.D) There is not enough information to decide.34. A student compared tuition, in thousands of dollars, for samples of public and private colleges/universities inNMeanStDevSE MeanPublic57.261.480.66Private632.323.301.3Difference = mu Public - mu PrivateEstimate for difference: ?25.06T-Test of difference = 0 (vs not =): T-Value = XXXX P-Value = 0.000 DF = 7This was aA) paired studyB) two-sample study35. Short-term parking rates were compared for a sample of 11 parking lots in a city?s downtown area, in 2007 vs NMeanStDevSE Mean2007117.774.431.34200811-0.6361.0020.302Difference11-0.6361.0020.302T-Test of mean difference = 0 (vs not = 0): T-Value = ?2.11 P-Value = 0.062The design wasA) pairedB) two-sampleC) several sample36. A masters thesis by M. Purser at the University of Washington in 1988 looked at soil densities in a conifer for area. These histograms show 32 pre-logging densities and 38 post-logging densities, recorded in grams per cu designs, this was a two-sample study: the same sample of soil could not be assessed twice.First compare the histograms? centers: when were the densities higher on average?A) before loggingB) after logging37. Is there a difference in mean hotel rates (five-night stay) for all hotels in Jamaica Curacao, and St. Lucia? An of hotels a each of the three resorts:Sample standard deviations areA) relatively closeB) quite different38. Is there a difference in mean hours slept for students in various years (1, 2, 3, 4, or other) at college? Analysis from several hundred students at a certain university:As far as the sample means are concerned, which group of students slept the longest?A) first yearB) second yearC) third yearD) fourth yearE) other39. Prices for samples of 16 new fiction, 16 non-fiction, and 10 advice books (all hardcover) were compared to d the same for the three types of book.The mean of any F curve is close to 1. What does the size of your F stati A) the P-value is smallB) the P-value is not small40. Miles driven (in thousands) were regressed on year for a sample of used Ford Mustangs.The regression equation isMiles = 10453 ? 5.20 YearPredictorCoefSE CoefTPConstant1045312568.320.000Year-5.20070.6261-8.310.000S = 8.629 R-Sq = 64.5% R-Sq(adj) = 63.6%Would a confidence interval for the slope contain zero?A) yesB) no41. Prices of a sample of generic drugs were regressed on the prices of the brand-name equivalents. The regression equation isGeneric = ?4.4 + 0.689 BrandPredictorCoefSE CoefTPConstantBrand-4.370.6887216.110.08865-0.277.770.7900.000S = 22.87 R-Sq = 78.0% R-Sq(adj) = 76.7%Predicted Values for New ObservationsNew ObsFitSE Fit1105.145.3795.0% CI(93.82, 116.46)95.0% PI(55.58, 154.70)Values of Predictors for New ObservationsNew ObsBrand1159The slope of the regression line for the relationship between all brand and generic prices isA) 0.689B) unknown, but almost surely positiveC) unknown, and it could easily be negative42.Which of these is true about the confidence interval (C.I.)?A) It estimates the mean of all responses to a given explanatory value.B) It estimates an individual response to a given explanatory value.43. A newspaper surveyed its readers about all of its comics, where possible responses were love it, hate it, or do ?hate it? was regressed on the count who responded ?love it? for a sample of 6 comics (Foxtrot, Zits, Blondie Family Circus).The regression equation isHateIt = 2346 ? 0.583 LoveItPredictorCoefSE CoefTPConstant2346.4235.39.970.001LoveIt-0.583470.09585-6.090.004S = 254.7 R-Sq = 90.3% R-Sq(adj) = 87.8%New Obs1Fit479SE Fit14195.0% CI(87, 872)95.0% PI(-329, 1288)Values of Predictors for New ObservationsNew ObsLoveIt13200Output is shown when interval estimates are requested for the number of people hating a comic, if 3,200 people plausible values for number hating a particular comic that was loved by 3,200 people?A) CIB) PI44. An annual state assessment test is a standards based criterion-referenced assessment used to measure a student while also determining the degree to which school programs enable students to attain proficiency of the stand relationships are considered: percentage passing versus school mean score, percentage passing versus percent school, and percentage passing versus percentage of disadvantaged students in the school.In this exercise, you are to identify which one of the three reported regression results corresponds to each of t 95% confidence interval for?1 for regression of % passing on mean (plot on the left)A) (?0.78,?0.50)B) (0.17, 0.20)C) (0.30,+1.61)45. regression line for regression of % passing on mean (plot on the left)A)? = -194 + 0.188xB)? = -55.4 + 0.953xC)? = 77.1 - 0.639x46. spread s about the line for regression of % passing on mean (plot on the left)A) 5.6B) 12.8C) 17.147. spread s about the line for regression of % passing on participated (plot in the middle)A) 5.6B) 12.8C) 17.148. t statistic to test if?1 = 0 for regression of % passing on participated (plot in the middle)A) ?9.05B) +2.90C) +27.9049. Scientists believe people?s ears get larger with age. They measured ear length in a sample ofpatients, aged 30 to 93, and found their ears grew about 0.01 inches a year.What type of study was this?A) sample surveyB) experimentC) observational study50. The explanatory variable isA) quantitativeB) categorical


Paper#61766 | Written in 18-Jul-2015

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