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Res 342 final exam Res 342 final exam Document Transcript

  • RES 342 Final ExamPLEASE DOWNLOAD THE ANSWERS HERE1. A statistician was setting up a hypothesis test with a level of significancedictated by upper management. However, she was concerned that the test shewished to perform might have unacceptable large possibilities of Type II error, ß.Which of the following would solve this problem 2. The area of rejection, on a bell shaped curve, defines the location of all thosevalues that are3. A hypothesis test that involves a small sample requires that we make thefollowing assumption that4. What are the critical z-values for a two-tailed hypothesis test if the significant ?5. K & S Construction, located in Phoenix, Arizona, is working on its businessplan for the upcoming year. They did a study to determine if they should focus onbuilding condominiums or individual houses. A building study, which had beenconducted by the state, indicated that 60 percent of those families looking to buya home in Arizona desired to buy a condominium. K & S Construction wanted toknow if this figure applied to Phoenix. They collected a sample of 500 individualsthat had expressed plans to buy a new home. The z-distribution was selected forthis proportion test. The null hypothesis is and the alternate is p ≠ 0.60. Thesignificant level selected was .05. From the sample of 500, it was determined that290 wanted to buy a condominium. What decision should be made regarding thenull hypothesis?6. Doi Winery has two wine shops in the neighboring towns of Seamen andBatavia. The favorite wine, as advertised, is Raspberry wine. A survey of 300customers at the Seamen store revealed that 225 individuals preferred theRaspberry wine while 290 out of 400 in Batavia preferred the same flavor. To testthe hypothesis that there was no difference in preferences in the two towns, whatis the alternate hypothesis?
  • 7. The Ohio Electric Company is investigating electric consumption by singlefamily homes based on the number of rooms. The investigators wanted todetermine the relationship between number of rooms and electric consumption inkilowatt-hours (thousands). A sample of 12 homes was selected and the data isas follows:Number of Rooms Kilowatt-Hours Number of Rooms Kilowatt-Hours10 10 8 99 8 10 117 6 10 912 13 8 987 6711 12 5 6What percent of the variation is explained by the variable, number of rooms?8. What randomness exists in the linear regression model?9. Smith’s Appliances is evaluating its advertising budget. The owner is trying todecide if the budget needs to be altered or not. The question: Is there a positivereturn on the investment that is being made in advertising? What is therelationship between sales and the amount spent on advertising? The ownercollected data for the past year by month. The data is in millions of dollars.Month Advertising Expense Sales RevenueJanuary 2 4February 3 5March 3 6April 5 8May 6 8June 4 7
  • July 5 7August 6 8September 7 9October 8 10November 10 13December 9 11Is there a relationship between the two variables? What is the coefficient ofcorrelation for this data?10. If the coefficient of correlation is 0.69, the coefficient of determination is11. In the least squares equation, Y = 12 + 25X the value of 25 indicates12. When an insurance company is going to write a new home owner policy, oneconcern is the distance between the house and the nearest fire departmentstation. This is one factor that goes in to determining the cost of the insurance forthe home owner. ETB Insurance Company wants to determine if there is arelationship between the distance to a fire station and the amount of fire damageto a house. A random sample of 50 claims was selected for analysis. Thecorrelation coefficient was 0.78. Which is the correct interpretation andrecommendation?13. Conducting a multiple regression analysis, the residual analysis is used to testthe requirement that14. In a multiple regression ANOVA table, explained variation is represented by15. If the net regression coefficients in the population are significantly differentfrom zero, what can be included?
  • 16. The time series component that reflects variability over short, repetitive timeperiods that last less than one year is called17. A time series is18. Given the trend equation Y = 24 + 0.6t (base ), what would be the forecastvalue for 2010?19. A research company has been hired by a reality company to do an analysisof heating cost of homes in the region. The reality company wanted to be able topredict the heating cost of a typical single family home. The realtor company wasconstantly being asked questions regarding heating costs by potential homebuyers. It was believed that these variables would impact heating costs (Y):mean daily outdoor temperature (X1), the number of inches of insulation (X2), theage in years of the furnace (X3). The multiple regression analysis produced thefollowing regression equation: Y = 427.2 – 4.58X1 – 14.83X2 + 6.10X3. Whichstatement is correct based on this analysis?20. With the increased cost in fuel, there has been a shift in the buying habits ofnew car purchasers. A local car dealer was interested in determining if there wasa significant difference in fuel efficiencies between three sizes of car: compact,midsize and large. The manager did a random sample of 27 cars. An ANOVAwas used as the analysis tool using a significant level of .01. The results of theANOVA were as follows:Source of Variation SS df MS F p-valueBetween Groups 130.44 2 65.22 7.97 0.00017Within Groups 196.24 24 8.18Total 326.68 36The manger’s decision would be21. Midwest State University Office of Registrar is reviewing the university’senrollment for the past 10 years. It is know that there are seasonal variable thataffects the university’s enrollment. To be better able to address business
  • decisions that are affected by enrollment, an analysis of data was necessary. Theschool operates on a quarter system of enrollment starting typically with fallquarter and ending with summer quarter. The analysis of the data produced thesefour quarterly indexes.Fall Winter Spring Summer1.2617 1.1896 1.040 0.4447Which statement is correct based on this analysis?22. A machine is set to fill the small size packages of Good and Better candiesare packaged with 60 pieces of candies in each bag. Sampling results revealed: 3bags of 61, 2 bags of 59, 1 bag of 58, and 2 bags of 62. How many degrees offreedom are there?23. Thomas Delivery has a fleet of 24 trucks that are utilized for the companies;business. Electro-Lite, a manufacturer of spark plugs, claims that its spark plugshave an average life in excess of 25,000 miles. The purchasing agent at ThomasDelivery purchased 24 sets and found that the sample average life was 26,300miles, the sample standard deviation was 1,500 miles, and the computed teststatistic was Based on these findings, at the 0.05 level, is there enough evidenceto accept the manufacturers claim?24. You are conducting a two-tailed test of means but your software packageonly calculates a one-tailed p-value equal to 0.13. The actual p-value for your testis25. Golf balls that are properly manufactured will have a rebound height of 42inches when dropped by a testing machine from a height of 5 feet. The qualitycontrol inspector is concerned that a new manufacturing machine is not properlycalibrated and that the resulting golf balls are falling short of the desired height. Atrandom, 100 golf balls were selected for a test. The test results indicated that therebound height was 41.6 inches with a standard deviation of 0.5. At the .05significant level, what is the result of the test?26. Flash Jolt, a manufacturer of camera equipment, annually introduces newmodels in the fall of the year. At the conclusion of the Christmas season, retaildealers are contacted regarding their stock on hand of each piece of equipment.It has been discovered that unless 47% of the new equipment ordered by the
  • retailers in the fall had been sold by Christmas, immediate production cutbacksare needed. At the end of the 2009 Christmas shopping season a survey of 100dealers indicated that 45% of Flash Jolt equipment had been sold. It was decidedto continue production levels at the current levels. The statistical test wasconducted at the 0.05 level. Computed z = –0.40.27. In a test for the equality of two variances (two-tailed), when the populationsare normal, a 5% level of significance was used. Sample sizes were and Theupper critical value for the test is28. The owner of a bottling company is considering buying a new bottlingmachine. He has been testing two different machines that are being considered.After collecting 300 samples from each machine over several weeks, he was ableto conduct a two sample z test.<p>He decided to utilize a 0.05 significant level forthe test. The test was to address the claim that the mean weight of the bottlesfilled by the Orno machine was greater than the mean weight of the bottles filledby the Edne machine. The test statistics was 2.21. What is the decision regardingthe hypothesis?29. Accounting procedures allow a business to evaluate their inventory at LIFO(Last In First Out) or FIFO (First In First Out). A manufacturer evaluated itsfinished goods inventory (in $ thousands) for five products both ways. Based onthe following results, is LIFO more effective in keeping the value of his inventorylower?Product FIFO (F) LIFO (L)1 225 2212 119 1003 100 1134 212 2005 248 245The 5% level of significance was selected for the t value. This example is whattype of test?30. Indy H2O is a water bottling company. They are looking at two differentbottling manufacturers’ equipment for the purpose of replacing some oldequipment. The net weights of a sample of bottles filled by a machine
  • manufactured by WTR, and the net weights of a sample filled by a similarmachine manufactured by Target are (in grams):WTR: 8, 9, 7, 8, 9, and 10Target: 8, 10, 7, 11, 9, 12, 8, and 9Testing the claim at the 0.05 level that the mean weight of the bottles filled by theTarget machine is greater than the mean weight of the bottles filled by the WTRmachine, what is the critical value?31. A consumer researcher is testing the difference between two proportions atthe 0.05 level of significance. The researcher was utilizing the z distribution forthe test. If the computed test statistic z value was 1.12, what was the decision? A. Do not reject the null hypothesis.32. Two different accounting procedures that are utilized by businesses as a wayto evaluate their inventory are LIFO (Last In First Out) and FIFO (First In FirstOut). ABC manufacturer evaluated its finished goods inventory (in $ thousands)for five products using both procedures. Based on the following results, is LIFOmore effective in keeping the value of his inventory lower?Product FIFO (F) LIFO (L)1 225 2212 119 1003 100 1134 212 2005 248 245The 5% level of significance was selected for the t value. The calculated teststatistic was 1.93. What is the decision?33. If the paired differences are normal in a test of mean differences, thedistribution used for testing is the 34. Watson’s TV claims that their televisions have the best performance recordon the market. They advertise that after 3 years only 10% of their sold televisionshave had any type of repairs. The president of the company wanted to confirmthat this statement was correct. To do this, a sample of 60 sets was taken of setsthat had been sold and were at least 3 years old. Twelve percent of these
  • television sets had been in for repair. The null hypothesis is that there is nodifference between the stated percent and the sample data. At the .05 significantlevel, what can we conclude about the null hypothesis? 35. The accountant for Thomas’s Furniture Store is concerned regarding theoutstanding receivable owed the company. There has been a cash flow problemand it is believed that the slow collection of accounts receivable is partially theblame. The accountant believes that 40% of the present accounts are more than4 months behind in making payments. To be able to make a decision regardingthis belief, a random sample of 100 accounts was taken. It was found that 37accounts were more than 4 months late. Did the sample data confirm theaccountant’s belief? Use the .05 significant level for the statistical test.36. New college business graduates are finding it difficult to get a job. A businessjournal has reported that only one in five graduates is able to find a job within 6months of their graduation. A report by the University of Phoenix indicated thatout of a survey of 300 recent business graduates, 75 had jobs. You are abusiness major at the University of Phoenix and have a concern about getting ajob. Based on this data, will a graduate of the University of Phoenix have a betterchance of getting a job in the first 6 months after graduation? Use the .05significant level for the test.37. Analysis of variance is used to38. The F distribution is utilized with the ANOVA test. There are some basicassumptions associated with the distribution. Which of these assumptions is NOTvalid?39. Blake’s Mortgage Company utilizes four different appraisers for the purposeof determining the value of a house. There is a concern by the company’s ownerthat the appraisers are not providing the same estimates. She wants to determineif there is a difference between the four appraisers. Six houses were selected andeach appraiser provided an appraisal for each of the six houses. What would bethe best statistical test to use for the analysis of this data?40. If an ANOVA test is conducted and the null hypothesis is rejected, what doesthis indicate?41. Ace Car Rental has three main models that are used in it midsize range ofcars. The cars are very similar and perform at about the same level. Since thecustomer has to pay for the gas use during the rental period, the manager is oftenasked about which car gets the best gas mileage. To be able to address thisquestion, an analysis was done of the three makes of cars. Each car can use anyone of four different grades of gasoline. The data collected was for each car foreach type of fuel. Performance was measured in miles per gallon. Perform anANOVA test and state the results.
  • Gasoline Model A Model B Model CRegular 21.4 22.3 20.8Super Regular 20.6 17.1 19.5Unleaded 21.3 19.2 20.2Premium 20.5 20.3 18.542. In ANOVA analysis, when the null hypothesis is rejected, we can find whichmeans are different by43. The chi-square has44. What nonparametric test is used when the assumptions for the parametricanalysis of variance (ANOVA) cannot be met? Its purpose is to test whether threeor more populations are equal. The data must be at least ordinal scaled.45. Which of the following values of Spearmans (rho) indicates the strongestrelationship between two variables?46. The nonparametric counterpart of the randomized block model of the ANOVAis the47. The city of Denver has several golf courses around the city. The RecreationalPark manager is trying to set the schedule for the employees at these courses.His concern is that he wants to have enough staff to handle the daily demandsbut to not be overstaffed. He has concerns about the next year’s budget and istrying to curb expenses where possible. To be able to make a decision regardingstaffing, he collected data regarding the number of rounds of golf played duringthe week. The weekend was excluded because the weekends are always verybusy. He wanted to see if there was a significant difference between the days ofthe week in terms of rounds being played. If there was a difference, then he coulduse this information to help make staffing decisions. The result of the datacollection is as follows:Day of Week RoundsMonday 150Tuesday 90Wednesday 120Thursday 100Friday 140
  • What is the result of the statistical test? Can the manager’s staff schedule vary fordifferent days of the week? Use the chi square distribution at the .05 significantlevel.48. Seamen’s Manufacturing has five hundred employees at its plant. Theseemployees are divided into three main groups: administration, clerical, and labor.The company is looking at making some changes to it retirement plan that isavailable for employees. There are three plans beginning considered. The 500employees were surveyed regarding their preferences for the various retirementplans. The president is concerned if there is a relationship between the personposition in the company and which retirement plan was preferred. Utilize the chisquare distribution at the .05 significant level, and determine if there is arelationship between position in company and the retirement plan selected.Position Plan A Plan B Plan CLabor 170 50 30Clerical 30 110 30Administration 20 20 4049. Clermont Savings and Loan has four branches located throughout thecounty. The activity level at these four branches appears to be different but themanger needs verification. Turnover rate, how quickly money is withdrawn froman account after being deposited, was selected as the variable to be measured. Atotal sample of 22 accounts was collected from the four Branches. The Kruskal-Wallis test, at the .01 significant level, was selected for the statistical analysis.The null hypothesis being tested was that the population distribution between thefour branches is identical. The test statistics was What is the correct interpretationof this result?50. Corny’s Feed Company markets four different mixtures of feed for chickens.These feeds have different combinations of ingredients. One question that themanager is often asked by customers is if there is a difference between the fourfeeds in terms of weight gain. To be able to address this question an analysis wasdone of the four feeds. They contacted a local farmer to conduct a test regardingthe four feeds. There were 28 chickens selected for the test. These chickenswere divided into four groups, with each group receiving one of the feeds. Thestatistical test selected for the analysis was the Kruskal-Wallis test and the .05significant level was used for the test. The test result was H 4.65. This indicatesthat51. What is your decision regarding the differences between the observed andexpected frequencies if the critical value of chi-square is 7.815 and the computedvalue is 6.789?
  • 52. Correlation coefficients of positive 0.88 and negative 0.88 representrelationships between two variables that have53. If the coefficient of multiple determination is 0.72, what percent of variation isnot explained?54. What is the measure that indicates how precise a prediction of Y is based onX or, conversely, how inaccurate the prediction might be?55. A manufacturer wants to increase the absorption capacity of a sponge. Basedon past data, the average sponge could absorb 3.5 ounces. An organic candlemanufacturer wants to increase the burning life of their candles. Changes weremade in the production process, which resulted in an improved candle. Todetermine if the changes had made a difference in the life of the candle, a testwas conducted. The length of burning time was collected for a sample of 10candles (time in hours): 4.1, 3.7, 3.3, 3.5, 3.8, 3.9, 3.6, 3.8, 4.0, and 3.9. What isthe decision rule at the 0.01 level of significance to test if the new designincreased the absorption amount of the sponge?56. The statement that determines if the null hypothesis is rejected or not is calledthe 57. Newton’s, a tire manufacturer, wanted to set a mileage guarantee on its newRoad Warrior 60 tire. A sample test of 500 tires revealed that the tire’s mileage isnormally distributed with a mean of 50,000 miles and a standard deviation of1,750 miles. The warranty on the tires is presently set at 47,500 miles. The z-teststatistic result was 1.43. The manufacturer wanted to determine if the tires wereexceeding the guarantee. At the .05 significant level, it was concluded that thetires are exceeding the manufacturer’s guarantee.58. When is it appropriate to use the paired difference t-test?59. What is the critical value for a one-tailed hypothesis test in which a nullhypothesis is tested at the 5% level of significance based on two samples, bothsample sizes are 13?60. When testing for differences between two means, the Behrens-Fisherproblem arises when the sample populations are61. If the decision is to reject the null hypothesis of no difference between twopopulation parameters, z distribution at the .01 significant level, what is thecorrect statement of the alternate hypothesis and rejection region?62. An independent consumer testing lab preformed a statistical test on 25 type-Calkaline batteries and calculated the mean life for a particular use before theyfailed was 22.5 hours. The distribution of the lives approximated a normal
  • distribution. The standard deviation of the distribution was 1.1 hours. Informationon the package states that the batteries should last 24 hours.The test question was if this difference between the test statistics and the statedlife of the battery was significant? The .05 significant level was selected for thetest. Which is the correct statement?63. Cake manufacturer Little Diva’s wants to increase the shelf life of its easy-to-fix cupcake mixes. Company’s records indicate that the average shelf life of themix is 230 days. A new, improved cupcake mix was developed and a sample of10 boxes of the cupcake mix had these shelf lives (in days): 231, 233, 232, 233,228, 231, 234, 229, 235, and 232. If the standard deviation was .67 and at the0.025 significant level, has the shelf life of the cupcake mix increased?64. Which of the following is NOT a reason one should have knowledge ofstatistics?65. The collection and summarization of the socioeconomic and physicalcharacteristics of the employees of a particular firm is an example of RES 342 Final ExamPLEASE DOWNLOAD THE ANSWERS HERE