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ECN 221 (Business Statistics) Exam 3 Practice Test fame MULTIPLE CIIOICE. Choose the one alternative that best completes the statement or answers the question. DA represents the width of the confidence interval between a sample mean anditsupper 1) limit or between a sample mean and its lower limit. A) confidence interval B) significance level D) confidence level ‘TRUE/FALSE. Write 'I" if the statement is true and 'F' if the statement is false. 2) The alternative hypothesis, denoted by Hj, represents the opposile of the null hypothesis and is 2) believed to be true if the null hypothesis is found to be false. 3) The sum of squares between ($SB) measures the variation between each sample mean and the 3) grand mean of the data. MULTIPLE CHOICE. Choosc the one alternative that best complctes the statement or answers the question. 4) Consider the partially completed one-way ANOVA summary table. 4) Sum of Degrees of [Mean Sum Source Squares Freedom of Squares |F Between [270 Within 18 Total 810 ai The degrees of freedom for the stim of squares between for this ANOVA procedure is A)2. B)4. cor) D)1. 5) The provides an estimate for the population variance if the mull hypothesis is true for 5) one-way ANOVA. A) lolal sum of squares B) mean square within ©) sum of squares error ‘TRUE/FALSE. Write '1" if the statement is true and 'F' if the statement is false. 6) The sum of squares within (SSW) measures the variation between each data value of the grand 6) mean for all of the data. 7) The degrees of freedom for the total sum of squares for one-way ANOVA equal the total number of 7) observations minus two. MUI TIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 8) The provides an estimate for the population variance whether or not the null hypothesis is true for one-way ANOVA. ©) mean square between 9) The sum of squares mean of the data. A) block B) within 10) Two real estate companies, Century 21 and RE/MAX, compete with onc another in a local market. The manager of the Century 21 office would like to advertise that homes listed with RE/MAX average more than 10 days on the market when compared to homes listed with his company. The following dala shows the sample size and average number of days on the market for the two B) total sum of squares D) sum of squares error companies along with the population standard deviations. Century 21 [RF/MAX Sample mean 122 days 144 days Sample size 36 30 Population standard deviation 32 days 35 days If Population 1 is defined as RE/MAX and Population 2 is defined as Century 21, and using a = 0.10, the conclusion for this hypothesis test would be because the test statistic is A) more than the critical value, the manager al Century 21 cannot claim that homes listed with RE/MAX average more than 10 days on the market when compared to homes listed with his company. ©) less than the critical value, the manager at Century 21 cannot claim that homes listed with RE/MAX average more than 10 days on the market when compared to homes listed with his company. D) less than the crilical value, the manager at Century 21 can claim that homes listed with RE/MAX average more than 10 days on the market when compared to homes listed with his company. rs) measures the variation between each sample mean and the grand D) error 8) 9) 10) 13) Progressive Insurance would like lo test the hypothesis thal a difference exists in the proportion of students in 12h grade who text while driving when compared to the proportion of 11th grade drivers who text. A random sample of 160 12th grade students found that 84 texted while driving. Arandom sample of 175 11h grade students found that 70 texted while driving. Lf Population 1 is defined as 12h grade drivers and Population 2 is defined as 11h grade drivers, the correct hypothesis statement for this hypothesis test would be ©) Ho: pt - p2 £9; Hi: pi - p2 > 0 D) Ho: pi - p2 <0; Hi: p1 - p2 20 14) Two real estate companies, Century 21 and RE/MAX, compete with one another in a local market ‘The manager of the Century 21 office would like to adverlise that homes listed with RE/MAX average more than 10 days on the market when compared to homes listed with his company. The following data shows the sample size and average number of days on the market for the two companics along with the population standard deviations. Century 21 [RE/MAX Sample mean 122 days 144 days Sample size 36 30 Population standard deviation 32 days 35 days If Population 1 is defined as RE/MAX and Population 2 is defined as Century 21, which one of the following statements is true? B) Because the 80% confidence interval includes 10, the manager at Century 21 can fail to reject the null hypothesis and claim that homes listed with RE/MAX average more than 10 days on the market when compared to homes listed with his company. C) Because the 80% confidence interval does not include zero, the manager at Century 21 can reject the null hypothesis and cannot claim that homes listed with RE/MAX average more than 10 days on the market when compared to homes listed with his company. 1) Because the 80% confidence interval includes zero, the manager at Century 21 can fail to reject the null hypothesis and claim that homes listed with RE/MAX average more than 10 days on the market when compared to homes listed with his company. 15) Sony would like to test the hypothesis that the average age of a PlayStation user is different from the average age of an Xbox user. A random sample of 36 PlayStation users had an average age of 34.2 years while a random sample of 30 Xbox users had an average age of 32.7 years. Assume that the population standard deviation for the age of PlayStation and Xbox users is 3.9 and 4.0 years, respectively. Sony would like to set = 0.10. The standard error of the difference between two means for this hypothesis lest would be B) 1.630 ©) 1.945 D) 0.503 14) 15) 16) Suppose Burger King has run a major advertising, campaign in the hopes of increasing monthly 16) sales. To investigate the effectiveness of this campaign, Burger King randomly selected six restaurants and recorded the monthly sales before and after the advertising. The following data represents these sales figures in thousands of dollars. Restaurant|1 2 3 4 5 6 Alter $123 $122 $145 $156 $160 $134 Before [$107 $110 $143. $168 $145. $125 Lf Population 1 is defined as sales after the advertising campaign and Population 2 is defined as sales before the advertising campaign, the standard deviation of the matched -pair differences is A) 15.72 B) 7.46 QO 1231 Db) 10.58 17) Two real estate companies, Century 21 and RE/MAX, compete with one another in a local market. 17) The manager of the Century 21 office would like to advertise that homes listed with RF/MAX average more than 10 days on the market when compared to homes listed with his company. The following dala shows the sample size and average number of days on the market for the two companies along with the population standard deviations. Century 21 [RE/MAX [Sample mean 122 days 144 days Sample size 36 30 Population standard deviation 32 days 35 days If Population 1 is defined as RE/MAX and Population 2 is defined as Century 21, the 80% confidence interval for the difference in population means is A) (17.8, 26.2) B) (-3.0, 47.0) © (11.5, 32.7), D) (6.4, 38.6) TRUE/TALSE. Write if the statement is true and 'T' if the statement is false. 18) When performing a hypothesis test comparing two population means, we need to assign 18) Population 1 to the larger sample mean and Population 2 to the smaller sample mean. MULTIPLE CHOICE. Chovse the one alternative that best completes the statement ur answers the question. 19) You have been assigned to test the hypothesis that the average number of hours per week thatan 19) American works is higher than the average number of hours per week thal a Swede works. The following data summarizes the sample statistics for the number of hours worked per week for workers in each country. Assume that the population variances are unequal [American| Swede Sample mean 32.7 hours 28.2 hours Sample size 15 12 [Sample standard deviation 5.1 hours 6.0 hours If Population 1 is defined as American workers and Population 2 is defined as Swedish workers, the degrees of freedom for this hypothesis test are . A) 25 +B) 21 ow 1D) 26 w MUI TIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 26) Many hotel chains that offer free Wi-Fi service to their customers have experienced increasing demand for Internet bandwidth and increasing costs. Marriott International would like to test the hypothesis that the proportion of customers that are carrying two Wi-Fi devices exceeds 0.40. A random sample of 130 Marriott customers found that 63 have two Wi-Fi devices. Marriott International would like to set a = 0.05. The conclusion for this hypothesis test would be that because the test statistic is B) less than the critical value, we can condude that the proportion of Marriott customers that carry two Wi-Fi devices is greater than 0.60 © more than the critical value, we can condude that the proportion of Marriott customers that carry two Wi-Fi devices is less than 0.60 D) more than the crilical value, we can conclude that the proportion of Marriott customers that carry two Wi-Fi devices is greater than 0.60 27) Many hotel chains thal offer free Wi-Fi service lo their customers have experienced increasing, demand for Internet bandwidth and increasing costs. Marriott International would like to test the hypothesis that the proportion of customers that are carrying two Wi-Fi devices exceeds 0.60. A random sample of 120 Marriott customers found that 78 have two Wi-Fi devices. Marriott International would like to set a = 0.01. The test statistic for this hypothesis test would be A)zp 158 B)zp 2.03 C) zp 1.80 28) The probability of a Type [ error is denoted as A) tho ‘B) alpha. © beta D) sigma 29) YouTube would like to test the hypothesis that the average length of an online video watched by a user is more than 8 minutes. A random sample of 37 people watched online videos that averaged 87 minules in length. Il is believed that the population standard deviation for the length of online videos is 2.5 minutes. YouTube would like to set a = 0.02. The test statistic for this hypothesis test would be A) £5 =2.06 B) #7=1.89 ©) 27 =2.23 Dyege170 30) The critical value for a two-tail hypothesis test when the population standard deviation is known, the sample size is 30 or more, anda 0.01 is . A) 2.05 ‘BY 2.575 ©) 2.96 D) 2.33 TRUE/FALSE. Write 'T' if the statement is true and 'F' if the statement is false. 31) The purpose of hypothesis statements is to draw a conclusion about the population parameters for which we do not have complete knowledge. 32) Because hypothesis testing relies on a sample, we expose ourselves to the risk that our conclusions about the population will be wrong because of a sampling error. 26) 27) 28) 29) 30) 32) MUI TIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 33) A professor would like to test the hypothesis that the average number of minutes that a student 33) needs to complete a statistics exam is equal to 45 minutes. A Type Il error would occur if the professor concludes that the average exam time is A) nol equal to 45 minutes when, in reality, the average time is greater than 45 minutes. 'B) equal to 45 minutes when, in reality, the average time is not equal to 45 minutes. C) not equal to 45 minutes when, in reality, the average time is equal to 45 minutes. D) equal lo 45 minutes when, in reality, the average lime is less than 45 minutes. 34) Steve's average golf score at his local course is 93.6 from a random sample of 34 rounds of golf. 34) Assume that the population standard deviation for his golf score is 4.2. The 90% confidence interval around this sample mean is B) (89.0, 98.3) © (93.2, 94.0) D) (90.5, 96.7) 35) A random sample of 25 roundtrip flights between Philadelphia and Dallas has an average airfare of 35) $393.50 with a sample standard deviation of $50.30. The critical value for an 80% confidence interval around this sample mean is B) L711 ©) 2.064 D) 0.857 36) Verizon Wireless would like to estimate the proportion af households that use cell phones for their 36) phone service without a land line. A random sample of 150 houscholds was sclected and 48 relied strictly on cell phones for their service. The 95% confidence interval for the proportion based on this sample is A) (0.223, 0.417) ‘B) (0.257, 0.383) ©) (0.165, 0.475) D) (0.185, 0.456) 37) "Gamers" are described as people who regularly play video games. A random sample of 80 people 37) was selected and 50 were found to be male. The 90% confidence interval for the proportion based on this sample is A) (0.463, 0.787) ‘B) (0.536, 0.714) ©) (0.571, 0.679) D) (0.598, 0.652) 38) Steve's average golf score at his local course is 92.9 from a random sample of 60 rounds of golf. 38) Assume that the population standard deviation for his golf score is 4.2. The standard error of the mean for this sample is A) L17 B) 2.30 ©) 0.54 D) 1.56 39) According to the Entertainment Software Association, the average age of "gamers" (those that 39) routinely play video games) is 30 years old. A random sample of 33 gamers people had an average age of 32.7 years old. Assume thal the population standard deviation for the age of gamers is 4.6 years. Use a 90% confidence interval to test the validity of this report and choose the one statement that is correct. A) Because this confidence interval does not include 30 years, the report by the Entertainment Software Association is validated. ©) Because this confidence interval does include 30 years, the report by the Entertainment Software Association is validated. D) Because this confidence interval does include 30 years, the report by the Entertainment Software Association is not validated. Answer Key Testname: PRACTICE.TEST.CII8-11 i} @ 2) TRUF, 3) TRUE 4c 5)D 6) TALS 7) FAISE. 8) A Cc 10) B Tic 12)D 13) A 14) A 15) A 16) D ye 18) FAT.SF. 19) B 20) D 2)C 22) TRUE 23) D 24) C 25) FALSE 26) A 27)D 28) B 29) D 30) B 31) TRUE 32) TRUE 33) B 34) A 35) A 36) B 37) B 38) C 39) B 40) D 41) TRUE 10 
