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Res 342 final exam Res 342 final exam Document Transcript

  • RES/342 Final Exam Answers are HERE!1) What are the critical z-values for a two-tailed hypothesis test if the significant level =0.01?A. ± 1.96B. ± 2.33C. ± 2.58D. ± 1.652) In classical hypothesis testing, the test statistic is to the critical value what the__________.A. ‘p-value’ is to alphaB. critical value is to alphaC. test statistic is to the ‘p-value’D. level of significance is to the test statistic3) For a hypothesis test of a single population mean at 95% confidence level, a calculated Zscore of 1.7 supports the conclusion thatA. the population mean is greater than the hypothesized valueB. the null hypothesis cannot be rejectedC. the sample is biasedD. the population mean is less than expected4) If the paired differences are normal in a test of mean differences, then the distributionused for testing is theA. normal distributionB. chi-squareC. student distributionD. F distribution5) One hundred women were polled and 60 reported successfully communicating anautomobile problem to an auto repairman. A sample of 150 men had 95 reporting the samesuccess. The value of the test statistic for a test of the equality of proportions isA. -0.5319B. 0.7293C. -0.419D. 0.27026) Weekly sales of iPods® at 20 Best Buy® stores are compared before and after installinga new eye-catching display. To determine if the display is effective in increasing sales, whattype of statistical test would you perform?A. Comparison of means using independent samples using a t-testB. Comparison of proportions using independent samples using a z-testC. Comparison of means using a paired z-testD. Comparison of means using a paired t-test7) When is it appropriate to use the paired difference t-test?
  • A. Four samples are compared at once.B. Any two samples are compared.C. Two independent samples are compared.D. Two dependent samples are compared.8) A survey of hotels found that the average hotel room rate in New Orleans is $88.42 andthe average room rate in Phoenix is $80.61. The survey sampled 50 hotels in each city. Thestandard deviations were $5.62 and $4.83, respectively. At alpha=.05, it can be concludedthat there is a significant different in the rates?A. 7.45B. -1.96C. 1.96D. -7.459) If the paired differences are normal in a test of mean differences, the distribution usedfor testing is theA. normal distributionB. chi-squareC. student t distributionD. F distribution10) The accountant for Thomas’s Furniture Store is concerned regarding the outstandingreceivable owed the company. There has been a cash flow problem and it is believed thatthe slow collection of accounts receivable is partially the blame. The accountant believesthat 40% of the present accounts are more than 4 months behind in making payments. Tobe able to make a decision regarding this belief, a random sample of 100 accounts wastaken. It was found that 37 accounts were more than 4 months late. Did the sample dataconfirm the accountant’s belief? Use the .05 significant level for the statistical test.A. There is not enough evidence to confirm or deny the belief.B. The accountants belief is not confirmed.C. The accountants belief is confirmed.D. The accountant needed to take a larger sample.11) New college business graduates are finding it difficult to get a job. A business journalhas reported that only one in five graduates is able to find a job within 6 months of theirgraduation. A report by University of Phoenix indicated that out of a survey of 300 recentbusiness graduates, 75 had jobs. You are a business major at University of Phoenix andhave a concern about getting a job. Based on this data, will a graduate of University ofPhoenix have a better chance of getting a job in the first 6 months after graduation? Usethe .05 significant level for the test.A. No, there is not a significant difference.B. It cannot be predicted based on this data.C. Yes, there is a significant difference.D. The business journal information is incorrect.12) Analysis of variance (ANOVA) is used toA. compare nominal dataB. compute t- testC. compare population proportionD. simultaneously compare several population means
  • 13) Mr. Thomas owns three different restaurants in Cincinnati, Ohio. He is concernedabout the profitability of the restaurants. There are monthly differences between therestaurants and he wants to determine if the differences in profit are significant. Mr.Thomas wants to do a statistical test to see if he should be concerned. The best test toaddress this problem would beA. a paired t- testB. two different t testsC. an ANOVA testD. a two sample test14) Sound engineers studied factors that might affect the output, in decibels, of a rockconcert’s speaker system. The desired level of significance was a = .05. The results of theirANOVA tests are shown:Source of Variation SS df MS F P-valueAmplifier 99.02344 99.02344 0.005718Position 93.98698 31.32899 3.215807 0.051003Interaction 10.15365 3 3.384549 0.347412 0.791505Error 155.875 16 9.742188Total 359.0391 23The interaction between the Position and Amplifier treatments wasA. very significantB. slightly significantC. insignificantD. highly correlated15) Totto, an automobile manufacturer, has designed a radically new engine and wants torecommend the grade of gasoline that will have the best fuel economy. The four grades areregular, below regular, premium, and super premium. The test car made three trial runson the test track using each of the grades and the miles per gallon were recorded. At the0.05 level, what is the critical value of F used to test the hypothesis that the miles per gallonfor each fuel are the same?A. 1.96B. 4.07C. 2.33D. 12.0016) If an ANOVA test is conducted and the null hypothesis is rejected, what does thisindicate?A. Too many degrees of freedomB. A difference between at least one pair of population meansC. No difference between the population meansD. The variances are the same17) Nonparametric statistics are used whenA. you have qualitative data, with your variables being measured at the nominal orinterval levelB. you have qualitative data, with your variables being measured at the ordinal or ratiolevelC. you have qualitative data, with your variables being measured at the nominal or ordinallevelD. you have qualitative data, with your variables being measured at the ordinal or intervallevel
  • 18) The nonparametric test most commonly used for testing the statistical independencebetween two variables isA. the Kruskal- Wallis testB. the Chi- Square testC. the Mann Whitney testD. the Sign test19) What nonparametric test is used when the assumptions for the parametric ANOVAcannot be met? Its purpose is to test whether three or more populations are equal. The datamust be at least ordinal scaled.A. Students’ tB. Kruskal- WallisC. Mann-WhitneyD. ANOVA20) Rachael Smith is the personnel manager at Johnson and Johnston, an accounting firm.She is concerned about absenteeism, which seems to be an increasing problem, especiallyafter days off work. She decided to sample the records to determine if absenteeism wasdistributed evenly throughout the 6-day work week. The null hypothesis to be tested was:Absenteeism is distributed evenly throughout the week. The sample results were:Day of Week Number AbsentMonday 12Tuesday 9Wednesday 11Thursday 10Friday 9Saturday 9What is the critical value of chi-square with a significant level of = 0.05?A. 11.070B. 12.592C. 13.388D. 15.03321) A public opinion poll surveyed a simple random sample of voters. Respondents wereclassified by gender and by voting preference—Republican, Democrat, or Independent.The results follow.Voting Preferences Republican Democrat Independent Row totalMale 200 150 50 400Female 250 300 50 600Column total 450 450 100 1000If you conduct a chi-square test of independence, what is the expected frequency count ofmale Independents?A. 50B. 60C. 40D. 3022) What parametric test is equivalent to the nonparametric Spearmans rank test?A. T-test of correlation coefficientB. T-test of two sample meansC. T-test of one sample mean.
  • D. T-test of two sample proportions23) What is the variable used to predict another variable called?A. Independent variableB. Dependent variableC. Moderating variableD. Intervening variable24) Michelle used a sample of 50 U.S. cities to estimate the relationship between crime, orannual property crimes per 100,000 persons, and income, or median income per capita.Her estimated regression equation was crime = 428 - .01 income. Assuming her model isstatistically significant, if income decreases by $1,000, we would predict that crime willA. decrease by 1B. increase by 10C. decrease by 10D. increase by 10025) In the least squares equation, Y = 12 + 25X the value of 25 indicatesA. the y- interceptB. for each unit increase in x, y increases by 25C. for each unit increase in y, x increases by 25D. the residual of x factor26) A test is conducted in eight cities to see if giving away free transit system maps willincrease bus ridership. In a regression analysis, the dependent variable is the increase inbus ridership in thousands of persons from the start of the test until its conclusion. Theindependent variables are X1 = the number in thousands of free maps distributed and X2 =a binary equal to 1, if the city has free downtown parking and 0 otherwise. The estimatedregression equation is Y = 1.32+.0345X1-1.45X2. If the Y value for city 3 is 7.3, X1 = 140,and X2 = 0 the residual for city 3 in thousands is:A. 6.34B. 1.15C. .57D. 2.0127) The following linear trend equation was developed for the annual sales of the TractorManufacturing Company. Y = 355 + 50t in thousands of dollars. How much are salesincreasing by?A. $50,000 per yearB. $5,00 per monthC. $500,000 per yearD. $6,000 per year28) The time series component that reflects variability over short, repetitive time periodsthat last less than one year is calledA. long-term trendB. cyclical variationC. seasonal variationD. irregular variation29) A research company has been hired by a realty company to do an analysis of heatingcost of homes in the region. The realty company wanted to be able to predict the heating
  • cost of a typical single-family home. The realty company was constantly being askedquestions regarding heating costs by potential home buyers. It was believed that thesevariables would impact heating costs (Y): mean daily outdoor temperature (X1), thenumber of inches of insulation (X2), and the age in years of the furnace (X3). The multipleregression analysis produced the following regression equation: Y = 427.2 – 4.58X1 –14.83X2 + 6.10X3. Which statement is correct based on this analysis?A. The age of the furnace has an indirect relationship with heating costs.B. There is an inverse relationship between outdoor temperature and heating costs.C. There is no real clear relationship between these variables.D. There exists a direct relationship between inches of insulation and heating costs.30) If we fit a linear trend to data that are growing exponentially,A. the fitted trend will be too high at the endB. the forecasts, if extrapolated, will be too lowC. the forecasts, if extrapolated, will be too highD. the fitted trend will be too low in the middle