《商务统计》见面课之答案

商务统计见面课之答案见面课：常见的假设检验及区间估计（双总体及多总体）1、问题: One rule that must always be followed in constructing frequency distributions is that _.选项：A:adjacent classes must not overlapB:the midpoint of each class must be a whole numberC:the width of each class is equal to the rangeD:the number of intervals must be an odd number答案: 【adjacent classes must not overlap】2、问题:image.png选项：A:are established correctlyB:are not mutually exclusivelyC:are not collectively exhaustiveD:don not reference a population parameter答案: 【are not collectively exhaustive】3、问题:When a false null hypothesis is not rejected, the researcher has made a选项：A: type II error.B: sampling error.C:powerful error.D: type I error答案: 【 type II error.】4、问题:image.png选项：A:image.pngB:image.pngC:image.pngD:image.png答案: 【image.png】5、问题:Which of the following is an appropriate null hypothesis?选项：A:image.pngB:image.pngC:image.pngD:image.png答案: 【image.png】6、问题:In what type of test is the variable of interest the difference between the values of the observations rather than the observations themselves?选项：A:a test for the equality of variances from 2 independent populationsB:a test for the difference between the means of 2 related populationsC:a test for the difference between the means of 2 independent populationsD:All of the above答案: 【All of the above】7、问题:The test for the equality of two population variances is based on the选项：A:ratio of the two sample variancesB:difference between the two sample variancesC:difference between the two population variancesD:difference between the sample variances divided by the difference between the sample means答案: 【ratio of the two sample variances】8、问题:image.png选项：A:zero.B:-0.5.C:0.5D:one.答案: 【0.5】9、问题:image.png选项：A:t distribution with 73 degrees of freedomB: t distribution with 72 degrees of freedom.C:t distribution with 71 degrees of freedomD: t distribution with 70 degrees of freedom.答案: 【 t distribution with 70 degrees of freedom.】10、问题:image.png选项：A:image.pngB:image.pngC:image.pngD:image.png答案: 【image.png】见面课：正确理解概率的含义及几种常见的概率统计分布1、问题:Given the following information:Standard deviation = 8 Coefficient of variation = 64%The mean would then be选项：A:12.5B: 8C:0.64D:1.25答案: 【12.5】2、问题:From a population of 500 elements, a sample of 225 elements is selected. It is known that the variance of the population is 900. The standard error of the mean is approximately选项：A:1.1022B:2C:30D:1.4847答案: 【1.4847】3、问题:A sample of 400 observations will be taken from an infinite population. The population proportion equals 0.8. The probability that the sample proportion will be greater than 0.83 is选项：A:0.4332B: 0.9332C:0.0668D: 0.5668答案: 【0.0668】4、问题:A weighted average of the value of a random variable, where the probability function provides weights is known as选项：A:a probability functionB: a random variableC:the expected valueD:random function答案: 【the expected value】5、问题:The student body of a large university consists of 60% female students. A random sample of 8 students is selected. What is the probability that among the students in the sample exactly two are female?选项：A:0.0896B:0.2936C:0.0413D:0.0007答案: 【0.0413】6、问题:image.pngimage.png选项：A:1.431B:2.047C:3.05D: 21答案: 【1.431】7、问题:Exhibit 2 The following represents the probability distribution for the daily demand of computers at a local store.image.png选项：A:0.7B:0.3C:0.4D:1.0答案: 【0.7】8、问题: If A and B are independent events, then选项：A: P(A) must be equal to P(B)B:P(A) must be greater than P(B)C:P(A) must be less than P(B)D:P(A) must be equal to P(AB)答案: 【P(A) must be equal to P(AB)】9、问题:The purpose of statistical inference is to provide information about the选项：A:sample based upon information contained in the populationB:population based upon information contained in the sampleC:population based upon information contained in the populationD:mean of the sample based upon the mean of the population答案: 【population based upon information contained in the sample】10、问题:A theorem that allows us to use the normal probability distribution to approximate the sampling distribution of sample means and sample proportions whenever the sample size is large is known as the选项：A:approximation theoremB:normal probability theoremC:central limit theoremD:central normality theorem答案: 【central limit theorem】见面课：相关分析及回归分析1、问题:If two variables, X and Y, have a strong linear relationship, then选项：A:There may or may not be any causal relationship between X and YB:X causes Y to happenC:Y causes X to happenD:None of these alternatives is correct答案: 【There may or may not be any causal relationship between X and Y】2、问题:In order to test for the significance of a regression model involving 14 independent variables and 255 observations, the numerator and denominator degrees of freedom (respectively) for the critical value of F are选项：A:14 and 255B:255 and 14C:14 and 240D:13 and 240答案: 【14 and 240】3、问题:In a multiple regression analysis model involving 2 independent variables and 15 observations, SSR = 268 and SST = 325. The adjusted coefficient of determination is选项：A:0.90B:0.80C:0.70D:Not enough information is provided to answer this question答案: 【0.80】4、问题:Which is considered to be a positive linear relationship选项：A:x goes up, y goes downB:x goes down, y goes upC:x goes down, y goes downD:x goes up, y goes upE:both c and d答案: 【both c and d】5、问题:In a regression analysis, if SSE is hypothetically decreased, then选项：A:R2 will DecreaseB:Se will IncreaseC:SST will decreaseD:Both a and bE:None of the above答案: 【None of the above】见面课：置信区间估计和假设检验（单总体）1、问题:deviation is the distance between a _ and the _.v选项：A:median, meanB:data point, meanC: quartile, medianD:data point, median答案: 【data point, mean】2、问题:The sum of the deviations may be 0.00. To get around this problem, we use the _ of the deviations选项：A: squareB:absolute valueC:minimumD: maximum答案: 【 square 】3、问题:The reason that we prefer the sample standard deviation as our measure of typical variation instead of the sample variance is that _选项：A: the variance is not as accurate a measurement as the standard deviationB:the standard deviation has been corrected for bias while the variance has notC:the standard deviation is in the same units as the data values.D:the variance is in the same units as the data values.答案: 【the standard deviation is in the same units as the data values.】4、问题:The empirical rule tells us that approximately of the values cluster within a distance of 1 standard deviation from the mean for a bell-shaped distribution选项：A:68%B:95%C:99.7%D:none of the above答案: 【68% 】5、问题:X is a discrete random variable that can have values from 0 to infinity, and occurrences of the events X counts are independent. The standard deviation of X is equal to the square root of the mean. The probability distribution of X is a(n) _distribution.选项：A: binomialB:uniformC:normalD:Possion答案: 【Possion】6、问题: When analyzing categorical data, stem and leaf display is an appropriate plot.选项：A:对B:错答案: 【错】7、问题: If the population distribution is unknown, in most cases the sampling distribution of the mean can be approximated by the normal distribution if the sample size is at least 15 observations选项：A:对B:错答案: 【错】8、问题:Statistical independence means the outcome of one event is independent of the outcome of a second event选项：A:对B:错答案: 【对】