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Statistics 30 question FINAL exam




Question;MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.1) The chancellor of a major university was concerned about alcohol abuse on her campus and wanted to find out the proportion of students at her university who visited campus bars on the weekend before the final exam week. Her assistant took a random sample of 250 students. The portion of students in the sample who visited campus bars on the weekend before the final exam week is an example of ________. 1) _______A) a statistic.B) a parameter. C) a population.D) a sample.2) Which of the following statistics is not a measure of central tendency? 2) _______A) arithmetic meanB) modeC) medianD)3) Data on the change in the cost of tuition, a shared dormitory room, and the most popular meal plan from the 20072008 academic year to the 20082009 academic year for a sample of 100 public universities are collected.Below is the boxplot for the change in cost in dollars. The distribution of the change in cost is3) _______A) none of the aboveB) symmetricalC) left-skewed D) right-skewed4) Which of the following is sensitive to extreme values? 4) _______A) the interquartile rangeB) the arithmetic meanC) the 1st quartileD) the median5) If two equally likely events A and B are mutually exclusive, what is the probability that event A occurs?_______A) 0.50B) 1.00C) 0D) Cannot be determined from the information given.6) In its standardized form, the normal distribution6) _______A) has an area equal to 0.5.B) has a mean of 0 and a standard deviation of 1.C) cannot be used to approximate discrete probability distributions.D) has a mean of 1 and a variance of 0.5)7) The owner of a fish market has an assistant who has determined that the weights of catfish are n ormally distributed,with mean of 3.2 pounds and standard deviation of 0.8 pound. If a sample of 16 fish is taken, what would the standarderror of the mean weight equal? 7) _______A) 0.200B) 0.800 C) 0.050 D) 0.0038) The head librarian at the Library of Congress has asked her assistant for an interval estimate of the mean number ofbooks checked out each day. The assistant provides the following interval estimate: from 740 to 920 books per day. If thehead librarian knows that the population standard deviation is 150 books checked out per day, and she asked herassistant for a 95% confidence interval, approximately how large a sample did her assistant use to determine the intervalestimate?8) _______A) 11B) 125 C) 4D) 139) A confidence interval was used to estimate the proportion of statistics students that are females. A random sample of72 statistics students generated the following 90% confidence interval: (0.438, 0.642). Based on the interval above, is thepopulation proportion of females equal to 0.60? 9) _______A) No. The proportion is 54.17%.B) Yes, and we are 90% sure of it.C) Maybe. 0.60 is a believable value of the population proportion based on the information above.D) No, and we are 90% sure of it.TABLE 9-6The quality control engineer for a furniture manufacturer is interested in the mean amount of force necessary to producecracks in stressed oak furniture. She performs a two -tail test of the null hypothesis that the mean for the stressed oakfurniture is 650. The calculated value of the Z test statistic is a positive number that leads to a p-value of 0.080 for the test.10) Referring to Table 9-6, suppose the engineer had decided that the alternative hypothesis to test was that the mean wasgreater than 650. What would be the p-value of this one-tail test? 10) ______A) 0.160B) 0.960 C) 0.040 D) 0.84011) How many tissues should the Kimberly Clark Corporation package of Kleenex contain? Researchers determined that60 tissues is the mean number of tissues used during a cold. Suppose a random sample of 100 Kleenex users yielded thefollowing data on the number of tissues used during a cold:= 52, S = 22. Suppose the test statistic does fall in therejection region at = 0.05. Which of the following decisions is correct? 11) ______A) At = 0.10, we do not reject H0.C) At = 0.05, we reject H0.B) At = 0.05, we accept H0.D) At = 0.05, we do not reject H0.TABLE 10-3The use of preservatives by food processors has become a controversial issue. Suppose 2 preservatives are extensivelytested and determined safe for use in meats. A processor wants to compare the preservatives for their effects on retardingspoilage. Suppose 15 cuts of fresh meat are treated with preservative I and 15 are treated with preservative II, and thenumber of hours until spoilage begins is recorded for each of the 30 cuts of meat. The results are summarized in the tablebelow.Preservative IPreservative III = 106.4 hoursSI = 10.3 hoursII = 96.54 hoursSII = 13.4 hours12) Referring to Table 10-3,12) ______A) There is evidence that the population variances between preservatives I and II are the same.B) There is evidence of a difference in the population variances between preservatives I and II.C) There is no evidence of a difference in the population variances between preservatives I and II.D) There is no evidence that the population variances between preservatives I and II are the same.TABLE 10-12The dean of a college is interested in the proportion of graduates from his college who have a job offer on graduation day.He is particularly interested in seeing if there is a difference in this prop ortion for accounting and economics majors. In arandom sample of 100 of each type of major at graduation, he found that 65 accounting majors and 52 economics majorshad job offers. If the accounting majors are designated as "Group 1" and the economics maj ors are designated as "Group2," perform the appropriate hypothesis test using a level of significance of 0.05.13) Referring to Table 10-12, the hypotheses the dean should use are:13) ______A) H0: 1 - 2 0 versus H1: 1 - 2 0 D) H0: 1 - 2 = 0 versus H1: 1 - 2 0TABLE 11-4A campus researcher wanted to investigate the factors that affect visitor travel time in a complex, multilevel bu ilding oncampus. Specifically, he wanted to determine whether different building signs (building maps versus wall signage) affectthe total amount of time visitors require to reach their destination and whether that time depends on whether the startinglocation is inside or outside the building. Three subjects were assigned to each of the combinations of signs and startinglocations, and travel time in seconds from beginning to destination was recorded. An Excel output of the appropriateanalysis is given below:ANOVASource of VariationSignsStarting LocationInteractionWithinSS14008.33122884835305.33Total61649.67dfMS14008.33F2.784395484413.167P-value0.112670.133740.919506F crit5.3176455.3176455.3176451114) Referring to Table 11-4, the F test statistic for testing the main effect of types of signs isA) 3.1742B) 0.0109C) 5.3176D) 2.784414) ______TABLE 13-11A computer software developer would like to use the number of downloads (in thousands) for the trial version of his newshareware to predict the amount of revenue (in thousands of dollars) he can make on the full version of the newshareware. Following is the output from a simple linear regression along with the residual plot and normal probabilityplot obtained from a data set of 30 different sharewares that he has developed:ANOVA15) Referring to Table 13-11, which of the following is the correct null hypothesis for testing whether there is a linearrelationship between revenue and the number of downloads?15) ______A) H0: 1 0B) H 0: 1 = 0C) H0: b1 = 0D) H0: b1 016) According to the empirical rule, if the data form a "bell -shaped" normal distribution, ________ percent of theobservations will be contained within 3 standard deviations around the arithmetic mean. 16) ______A) 68.26B) 95.0 C) 75.00 D) 99.717) If a particular batch of data is approximately normally distributed, we would find that approximately 17) ______A) 4 of every 5 observations would fall between 1.28 standard deviations around the mean.B) 2 of every 3 observations would fall between 1 standard deviation around the mean.C) 19 of every 20 observations would fall between 2 standard deviations around the mean.D) All of the above.18) A population frame for a survey contains a listing of 6,179 names. Using a table of random numbers, which of thefollowing code numbers will appear on your list?18) ______A) 0694 B) 61790C) 6946 D) 0619) Suppose a 95% confidence interval for turns out to be (1,000, 2,100). Give a definition of what it means to be "95%confident" in an inference.19) ______A) 95% of the observations in the entire population fall in the given interval.B) In repeated sampling, the population parameter would fall in the given interval 95% of the time.C) In repeated sampling, 95% of the intervals constructed would contain the population mean.D) 95% of the observations in the sample fall in the given int erval.TABLE 9-4A drug company is considering marketing a new local anesthetic. The effective time of the anesthetic the drug company iscurrently producing has a normal distribution with an mean of 7.4 minutes with a standard deviation of 1.2 minutes. Thechemistry of the new anesthetic is such that the effective time should be normally distributed with the same standarddeviation, but the mean effective time may be lower. If it is lower, the drug company will market the new anesthetic,otherwise, they will continue to produce the older one. A sample of size 36 results in a sample mean of 7.1. A hypothesistest will be done to help make the decision.20) Referring to Table 9-4, the appropriate hypotheses are:20) ______A) H0: = 7.4 versus H1: 7.4B) H0: 7.4 versus H1: > 7.4C) H0: > 7.4 versus H1: 7.4D) H0: 7.4 versus H1: F10.760.0014.364430) Referring to Table 11-3, the critical value of Levene's test for homogeneity of variances at a 5% level of significance is30) ______A) 3.29 B) 0.64 C) 3.49 D) 2.48


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