Business Statistics Review SectionsTrue or Fal F1 A continuous variable may take on any value within its relevant range even though theMeasurement device may not be preci enough to record it.
英国约克F 2 A Marine drill instructor recorded the time in which each of 11 recruits completed anobstacle cour both before and after basic training. To test whether any improvement occurred,the instructor would u a t-distribution with 11 degrees of freedom.T3 A sampling distribution is a distribution for a statistic.T4 A test for the difference between two proportions can be performed using the chi-squaredistribution.F5 As the size of the sample is incread, the standard deviation of the sampling distribution ofthe sample mean for a normally distributed population will stay the same.To型血和a型血生的孩子是什么血型6 Determining a college student’s academic major would be an example of measurement on anominal scale of measurement.T 7 For a given level of significance, if the sample size is incread, the power of the test willincrea.F8 For a given level of significance, if the sample size is incread, the probability ofcommitting a Type I error will increa.T9 For all two-sample tests, the sample sizes must be equal in the 2 groups.T 10 Histograms are ud for numeri
cal data while bar charts are suitable for categorical data.F 11 If P(A) = 0.4 and P(B) = 0.6, then A and B must be collectively exhaustive.T 12 If the population distribution is symmetric, the sampling distribution of the mean can beapproximated by the normal distribution if the samples contain 15 obrvations.F13 In a chi-square test, it is possible for the obrved frequencies to be fractions or decimalvalues.T 14 In a one-factor ANOVA analysis, the among sum of squares and within sum of squares mustadd up to the total sum of squares.F 15 In forming a 90% confidence interval for a population mean from a sample size of 22, thenumber of degrees of freedom from the t distribution equals 22.F 16 In testing the difference between two proportions using the normal distribution, we may ueither a one-tailed Chi-square test or two-tailed Z test.17 Ogives are plotted at the midpoints of the class groupings.T 18 Other things being equal, as the confidence level for a confidence interval increas, thewidth of the interval increas.T 19 Repeated measurements from the same individuals is an example of data collected from 2related populations.F 20 Student grades (A to F) are an example of continuous numerical data.F 21 The analysis of variance (ANOVA) tests hypothes about the population variance.F 2
2 The answer to the question “What is your favorite color?” is an example of an ordinal scaledvariable.F23 The coefficient of variation measures variability in a data t relative to the size of thearithmetic mean.F 24 The F distribution is symmetric.T25 The interquartile range is a measure of variation or dispersion in a t of data.F 26 The median of the values 3.4, 4.7, 1.9, 7.6, and 6.5 is 1.9.F 27 The median of the values 3.4, 4.7, 1.9, 7.6, and 6.5 is 4.05.F28 The number of customers arriving at a department store in a 5-minute period has a binomialdistribution.F29 The probability that a standard normal random variable, Z, falls between –2.00 and –0.44 is0.6472.T30 The prob ability that a standard normal random variable, Z, is between 1.50 and 2.10 is thesame as the probability Z is between – 2.10 and – 1.50.T 31 The smaller is the p-value, the stronger is the evidence against the null hypothesis.T 32 The sum of cumulative frequencies in a distribution always equals 1.F 33 The sum of relative frequencies in a distribution always equals 1.F 34 When A and B are mutually exclusive, P(A or B) can be found by adding P(A) and P(B).T 35 When the F test is ud for ANOVA, the rejection region is always in the right tail.T 36 A rearcher is curious about the effect of sleep on students’ test perfor
mances. He choos60 students and gives each 2 tests: one given after 2 hours’ sleep and one after 8 hours’ sleep. Thetest the rearcher should u would be a related samples test.T 37 A sample is the portion of the univer that is lected for analysis.F 38 In a Poisson distribution, the mean and variance are equal.T 39 The larger is the p-value, the more likely one is to reject the null hypothesis.T 40 The number of customers arriving at a department store in a 5-minute period has a Poissondistribution.
ChoiceA The process of using sample statistics to draw conclusions about true population parameters iscalled(A) statistical inference. (B) the scientific method.(C) sampling. (D) descriptive statistics.D Tho methods involving the collection, prentation, and characterization of a t of data in order to properly describe the various features of that t of data are called(A) statistical inference. (B) the scientific method.(C) sampling. (D) descriptive statistics.C The collection and summarization of the socioeconomic and physical characteristics of theemployees of a particular firm is an example of(A) inferential statistics. (B) descriptive statistics.(C) a parameter. (D) a statistic.D The estimation of the population average family expenditure on food bad on
the sample average expenditure of 1,000 families is an example of(A) inferential statistics. (B) descriptive statistics.(C) a parameter. (D) a statistic.B The univer or "totality of items or things" under consideration is called(A) a sample. (B) a population.(C) a parameter. (D) a statistic.A The portion of the univer that has been lected for analysis is called(A) a sample. (B) a frame. (C) a parameter. (D) a statistic.B A summary measure that is computed to describe a characteristic of an entire population is called(A) a census. (B) a parameter. (C) a statistic. (D) the scientific method.C A summary measure that is computed to describe a characteristic from only a sample of thepopulation is called(A) a parameter. (B) a census. (C) a statistic. (D) the scientificmethod.D Which of the following is most likely a population as oppod to a sample?(A) respondents to a newspaper survey. (B) the first 5 students completing an assignment.(C) every third person to arrive at the bank. (D) registered voters in a county.中文信件格式A When studying the simultaneous respons to two categorical questions, we should t up a(A) contingency table. (B)frequency distribution table.(C)cumulative percentage distribution table. (D)histogram.B which of the following is most likely a param
eter as oppod to a statistic?(A) The average score of the first five students completing an assignment.(B) The proportion of females registered to vote in a county.(C) The average height of people randomly lected from a databa.(D) The proportion of trucks stopped yesterday that were cited for bad brakes.游洞庭湖B When polygons or histograms are constructed, which axis must show the true zero or "origin"?(A) The horizontal axis. (B) The vertical axis.(C) Both the horizontal and vertical axes. (D) Neither the horizontal nor the vertical axis.A A survey of 150 executives were asked what they think is the most common mistake candidatesmake during job interviews. Six different mistakes were given. Which of the following is thebest for prenting the information?(A) A bar chart. (B) A histogram(C) A stem-and-leaf display. (D) A contingency table.D Which of the following statistics is not a measure of central tendency?(A) Arithmetic mean. (B) Median. (C) Mode. (D) Q3.A You have collected information on the market share of 5 different arch engines ud by U.S.Internet urs in May 2007. Which of the following is the best for prenting the information?(A) A pie chart. (B) A histogram(C) A stem-and-leaf display. (D) A contingency table.Which measure of central tendency can be ud for both numeric
al and categorical variables?(A) Arithmetic mean. (B) Median. (C) Mode. (D) Standard deviation.D In a right-skewed distribution(A) the median equals the arithmetic mean (B) the median is less than the arithmetic mean.(C) the median is larger than the arithmetic mean. (D) none of the above.C If two events are collectively exhaustive, what is the probability that both occur at the same time?(A) 0. (B) 0.50.(C) 1.00. (D)Cannot be determined from the information given.C In a perfectly symmetrical distribution(A) the range equals the interquartile range.(B) the interquartile range equals the arithmetic mean.(C) the median equals the arithmetic mean.(D) the variance equals the standard deviation.
D If two events are mutually exclusive, what is the probability that one or the other occurs?(A) 0. (B) 0.50. (C) 1.00. (D) Cannot be determined from theinformation given.A Simple probability is also called(A) marginal probability. (B) joint probability.(C) conditional probability. (D) Bayes' theorem.B If the outcome of event A is not affected by event B, then events A and B are said to be(A) mutually exclusive. (B) statistically independent.(C) collectively exhaustive. (D) None of the above.B Which of the following about the binomia
l distribution is not a true statement?(A) The probability of event of interest must be constant from trial to trial.(B) Each outcome is independent of the other.(C) Each outcome may be classified as either "event of interest" or "not event of interest."(D) The random variable of interest is continuous.C Which of the following about the normal distribution is not true?(A) Theoretically, the mean, median, and mode are the same.(B) About 2/3 of the obrvations fall within 1 standard deviation from the mean.(C) It is a discrete probability distribution.(D) Its parameters are the mean, , and standard deviation, .C If n = 10 and p = 0.70, then the mean of the binomial distribution is(A) 0.07 (B) 1.45. (C) 7.00 (D) 14.29C In its standardized form, the normal distribution(A) has a mean of 0 and a standard deviation of 1.(B) has a mean of 1 and a variance of 0.(C) has an area equal to 0.5.(D) cannot be ud to approximate discrete probability distributions.D If we know that the length of time it takes a college student to find a parking spot in the libraryparking lot follows a normal distribution with a mean of 3.5 minutes and a standard deviation of 1minute, find the point in the distribution in which 75.8% of the college students exceed whentrying to find a parking spot in the library parking lot.
(A) 2.8 minutes (B) 3.2 minutes (C) 3.4 minutes (D) 4.2 minutesD If we know that the length of time it takes a college student to find a parking spot in the libraryparking lot follows a normal distribution with a mean of 3.5 minutes and a standard deviation of 1minute, find the probability that a randomly lected college student will take between 2 and 4.5minutes to find a parking spot in the library parking lot.(A) 0.0919 (B) 0.2255 (C) 0.4938 (D) 0.7745A Which of the following statements about the sampling distribution of the sample mean isincorrect?(A) The sampling distribution of the sample mean is approximately normal whenever the samplesize is sufficiently large
(B) The sampling distribution of the sample mean is generated by repeatedly taking samples ofsize n and computing the sample means.(C) The mean of the sampling distribution of the sample mean is equal to μ .(D) The standard deviation of the sampling distribution of the sample mean is equal to σ .C The width of a confidence interval estimate for a proportion will be(A) narrower for 99% confidence than for 95% confidence.(B) wider for a sample size of 100 than for a sample size of 50.(C) narrower for 90% confidence than for 95% confidence.(D) narrower when the sample proportion is
0.50 than when the sample proportion is 0.20.A Which of the following would be an appropriate null hypothesis?(A) The mean of a population is equal to 55.(B) The mean of a sample is equal to 55.(C) The mean of a population is greater than 55.(D) Only (A) and (C) are true.B Sampling distributions describe the distribution of(A) parameters. (B) statistics.(C) both parameters and statistics. (D) neither parameters nor statistics.D The t distribution(A) assumes the population is normally distributed.(B) approaches the normal distribution as the sample size increas.
(C) has more area in the tails than does the normal distribution.(D) All of the above.C Which of the following would be an appropriate null hypothesis?(A) The population proportion is less than 0.65.(B) The sample proportion is less than 0.65.(C) The population proportion is no less than 0.65.(D) The sample proportion is no less than 0.65.B 盐酸倍他司汀The t test for the difference between the means of 2 independent populations assumes that therespective(A) sample sizes are equal. (B)sample variances are equal.(C) populations are approximately normal. (D)All of the above.A The t test for the mean difference between 2 related populations assumes that the(A) population sizes are equal.
(B) sample variances are equal.(C) population of differences is approximately normal or sample sizes are large enough.(D) All of the above.让赞美飞扬>树立正确的人生观D The statistical distribution ud for testing the difference between two population variances is the___ distribution.(A) t (B) standardized normal (C)binomial (D) FA The test for the equality of two population variances is bad on(A) the difference between the 2 sample variances.(B) the ratio of the 2 sample variances.(C) the difference between the 2 population variances.(D) the difference between the sample variances divided by the difference between the samplemeans.A萧萧黄叶闭疏窗 In a one-wayANOVA, the null hypothesis is always(A) there is no treatment effect. (B) there is some treatment effect.(C) all the population means are different. (D) some of the population means are different.D Why would you u the Tukey-Kramer procedure?(A) To test for normality. (B) To test for homogeneity of variance.(C) To test independence of errors. (D) To test for differences in pairwimeans.Calculation1 EstimationThe president of a university would like to estimate the proportion of the student populationthat owns a personal computer. In a sample of 500 students, 417 own a personal computer.What is the 99% confidence interval for the proportion of student population who own a personal computer ?
