《Business statistic》复习参考(第一章至第八章)

Business Statistic中国人民大学出版社 英文版 第五版 chapter18复习参考Part1名词解释1、 Statistics is a method of extracting useful information from a set of numerical data in order to make a more effective and informed decision.2、 Descriptive Statistics：These are statistical methods of organizing, summarizing and presenting numerical data in convenient forms such as graphs, charts and tables.3、 Inferential statistics is defined as statistical methods used for drawing conclusions about a population based on samples.4、 Primary data is obtained first hand. 5、 Secondary data already exists or has been previously collected such as company accounts, or sales figures.6、 Mean: The arithmetic average and the most common measure ofaaaaaaa central tendency. All values are included in computing the mean.A set of data has a unique mean The mean is affected by unusually large or small data points (outliers / extreme values).7、 Mode: The most frequent data, or data corresponding to the highest frequency. Mode is not affected by extreme values. There may not be a mode. There may be several modes. Used for either numerical or categorical data.8、 Median is the value that splits a ranked set of data into two equal parts. Median is not affected by extremely large or small values and is therefore a valuable measure of central tendency when such values occur.9、 Standard Deviation: A measure of the variation of data from the mean. The most commonly used measure of variation. Represented by the symbol s. Shows how the data is distributed around the mean.10、 Probability is the chance of an occurrence of an event. Probability of an event always lies between 0 and 1. The sum of the probabilities of every possible outcome or event is 1. The probability of the complement A is given by 1-P(A).11、 Properties of Normal distribution：Continuous random variable. Bell-shaped & symmetrical. Mean, median, mode are equal Area under the curve is 1.12、 The Central Limited Theorem：If the population followed normal distribution, the sampling distribution of mean is followed normal distribution. If the population do not followed normal distribution, but the sample size is larger than 30, the sampling distribution of mean is followed normal distribution.Part2选择题Topic 1 - Introduction to Business Statistics & Data CollectionQ1. The universe or totality of items or things under consideration is called:a. a sample. b. a population. c. a parameter. d. none of the above. Q2. Those methods involving the collection, presentation, and characterization of a set of data in order to properly describe the various features of that set of data are called:a. inferential statistics. b. total quality management. c. sampling. d. descriptive statistics. Q3. The portion of the universe that has been selected for analysis is called:a. a sample. b. a frame. c. a parameter. d. a statistic. Q4. A summary measure that is computed to describe a numerical characteristic from only a sample of the population is called:a. a parameter. b. a census. c. a statistic. d. the scientific method. Q5. A summary measure that is computed to describe a characteristic of an entire population is called:a. a parameter. b. a census. c. a statistic. d. total quality management. Q6. The process of using sample statistics to draw conclusions about population parameters is called:a. inferential statistics. b. experimentation. c. primary sources. d. descriptive statistics. Q7. Which of the four methods of data collection is involved when a person retrieves data from an online database?a. published sources. b. experimentation. c. surveying. d. observation. Q8. Which of the four methods of data collection is involved when people are asked to complete a questionnaire?a. published sources. b. experimentation. c. surveying. d. observation. Q9. Which of the four methods of data collection is involved when a person records the use of the Los Angeles freeway system?a. published sources. b. experimentation. c. surveying. d. observation. Q10. A focus group is an example of which of the four methods of data collection?a. published sources. b. experimentation. c. surveying. d. observation. Q11. Which of the following is true about response rates?a. The longer the questionnaire, the lower the rate. b. Mail surveys usually produce lower response rates than personal interviews or telephone surveys. c. Question wording can affect a response rate. d. d. All of the above. Q12. Which of the following is a reason that a manager needs to know about statistics?a. To know how to properly present and describe information. b. To know how to draw conclusions about the population based on sample information. c. To know how to improve processes. d. All of the above. Scenario 1-1Questions 13-15 refer to this scenario:An insurance company evaluates many variables about a person before deciding on an appropriate rate for automobile insurance. Some of these variables can be classified as categorical, discrete and numerical, or continuous and numerical. Q13. Referring to Scenario 1-1 (above), the number of claims a person has made in the last three years is what type of variable?a. Categorical. b. Discrete and numerical. c. Continuous and numerical. d. None of the above. Q14. Referring to Scenario 1-1 (above), a persons age is what type of variable?a. Categorical. b. Discrete and numerical. c. Continuous and numerical. d. None of the above. Q15. Referring to Scenario 1-1 (above), a persons gender is what type of variable?a. Categorical. b. Discrete and numerical. c. Continuous and numerical. d. None of the above. Q16. Which of the following can be reduced by proper interviewer training?a. Sampling error. b. Measurement error. c. Coverage error. d. Nonresponse error. Scenario 1-2Questions 17-19 refer to this scenario:Mediterranean fruit flies were discovered in California a few years ago and badly damaged the oranges grown in that state. Suppose the manager of a large farm wanted to study the impact of the fruit flies on the orange crops on a daily basis over a 6-week period. On each day a random sample of orange trees was selected from within a random sample of acres. The daily average number of damaged oranges per tree and the proportion of trees having damaged oranges were calculated. Q17. Referring to Scenario 1-2 (above), the two main measures calculated each day (i.e., average number of damaged oranges per tree and proportion of trees having damaged oranges) are called _.a. statistics. b. parameters. c. samples. d. populations. Q18. Referring to Scenario 1-2 (above), the two main measures calculated each day (i.e., average number of damaged oranges per tree and proportion of trees having damaged oranges) may be used on a daily basis to estimate the respective true population _.a. estimates. b. parameters. c. statistics. d. frame. Q19. Referring to Scenario 1-2 (above), in this study, drawing conclusions on any one day about the true population characteristics based on information obtained from the sample is called _.a. evaluation. b. descriptive statistics. c. inferential statistics. d. survey. Scenario 1-3Questions 20 and 21 refer to this scenario:The Quality Assurance Department of a large urban hospital is attempting to monitor and evaluate patient satisfaction with hospital services. Prior to discharge, a random sample of patients is asked to fill out a questionnaire to rate such services as medical care, nursing, therapy, laboratory, food, and cleaning. The Quality Assurance Department prepares weekly reports that are presented at the Board of Directors meetings and extraordinary/atypical ratings are easy to flag.Q20. Referring to Scenario 1-3 (above), true population characteristics estimated from the sample results each week are called _.a. inferences. b. parameters. c. estimates. d. data. Q21. Referring to Scenario 1-3 (above), a listing of all hospitalised patients in this institution over a particular week would constitute the _.a. sample. b. population. c. statistics. d. parameters. Scenario 1-4Questions 22-24 refer to this scenario:The following are the questions given to Sheila Drucker-Ferris in her college alumni association survey. Each variable can be classified as categorical or numerical, discrete or continuous.Q22. Referring to Scenario 1-4 (above), the data for the number of years since graduation is categorised as: _.a. numerical discrete. b. categorical. c. numerical continuous. d. none of the above. Q23. Referring to Scenario 1-4 (above), the data for the number of science majors is categorised as: _.a. categorical. b. numerical continuous. c. numerical discrete. d. none of the above. Q24. Referring to Scenario 1-4 (above), the data for tabulating the level of job satisfaction (High, Moderate, Low) is categorised as: _.a. numerical continuous. b. categorical. c. numerical discrete. d. none of the above. Topic 2: Organising and Presenting dataQ1 The width of each bar in a histogram corresponds to the:a. boundaries of the classes. b. number of observations in the classes. c. midpoint of the classes. d. percentage of observations in the classes. Q2 When constructing charts, which of the following chart types is plotted at the class midpoints?a. Frequency histograms. b. Percentage polygons. c. Cumulative relative frequency ogives. d. Relative frequency histograms. Q3 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. Q4 To determine the appropriate width of each class interval in a grouped frequency distribution, we:a. divide the range of the data by the number of desired class intervals. b. divide the number of desired class intervals by the range of the datac. take the square root of the number of observations. d. take the square of the number of observations. Q5 When grouping data into classes it is recommended that we have:a. less than 5 classes. b. between 5 and 15 classes. c. more than 15 classes. d. between 10 and 30 classes. Q6 Which of the following charts would give you information regarding the number of observations up to and including a given group?a. Frequency histograms. b. Polygons. c. Percentage polygons. d. Cumulative relative frequency ogives. Q7 Another name for an ogive is a:a. frequency histogram. b. polygon. c. percentage polygon. d. cumulative percentage polygon. Q8 In analyzing categorical data, the following graphical device is NOT appropriate:a. bar chart. b. Pareto diagram. c. stem and leaf display. d. pie chart. Table 2The opinions of a sample of 200 people broken down by gender about the latest congressional plan to eliminate anti-trust exemptions for professional baseball. For NeutralAgainstTotalsFemale385412104Male12364896Totals509060200Q9 Table 2 (above) contains the opinions of a sample of 200 people broken down by gender about the latest congressional plan to eliminate anti-trust exemptions for professional baseball.Referring to Table 2, the number of people who are neutral to the plan is _.a. 36 b. 54 c. 90 d. 200 Q10 Referring to Table 2, the number of males who are against the plan is _.a. 12 b. 48 c. 60 d. 96 Q11 Referring to Table 2, the percentage of males among those who are for the plan is _.a. 12.5% b. 24% c. 25% d. 76% Q12 Referring to Table 2, the percentage who are against the plan among the females is _.a. 11.54% b. 20% c. 30% d. 52% Topic 3: Numerical Descriptive StatisticsQ1 Which measure of central tendency can be used for both numerical and categorical variables? a. Mean. b. Median. c. Mode. d. Quartiles. Q2 Which of the following statistics is not a measure of central tendency? a. Mean. b. Median. c. Mode. d. Q3. Q3 Which of the following statements about the median is NOT true? a. It is more affected by extreme values than the mean. b. It is a measure of central tendency. c. It is equal to Q2. d. It is equal to the mode in bell-shaped distributions. Q4 The value in a data set that appears most frequently is called: a. the median. b. the mode. c. the mean. d. the variance. Q5 In a perfectly symmetrical distribution: a. the mean equals the median. b. the median equals the mode. c. the mean equals the mode. d. All of the above. Q6 When extreme values are present in a set of data, which of the following descriptive summary measures are most appropriate? a. CV and range. b. Mean and standard deviation. c. Median and interquartile range. d. Mode and variance. Q7 The smaller the spread of scores around the mean: a. the smaller the interquartile range. b. the smaller the standard deviation. c. the smaller the coefficient of variation. d. All the above. Q8 In a right-skewed distribution: a. the median equals the mean. b. the mean is less than the median. c. the mean is greater than the median. d. the mean is less than the mode. The data below represents the amount of grams of carbohydrates in a serving of breakfast cereal.Table 31115232919222120152517Q9 Referring to Table 3 (above), the mean carbohydrates in this sample is _ grams. a. 15.25 b. 19.73 c. 21.42 d. 21.70 Q10 Referring to Table 3 (above), the median carbohydrate amount in the cereal is _ grams. a. 19 b. 20 c. 21 d. 21.5 Q11 Referring to Table 3 (above), the 1st quartile of the carbohydrate amounts is _ grams. a. 15 b. 20 c. 21 d. 25 Q12 Referring to Table 3 (above), the range in the carbohydrate amounts is _ grams. a. 16 b. 18 c. 20 d. 21 Topic 4: Basics probability and discrete probability distributionsInformation A, needed to answer Questions 1 to 2The Health and Safety committee in a large retail firm is examining the relationship between the number of days of sick leave an employee takes and whether an employee works on the day shift (D) or night shift (N). The committee looks at a sample of 50 employees and notes which shift they work on and whether the number of days of sick leave they take in a year is less than 6 days (L) or 6 or more days (M). The information they obtain is shown below. Table 4-1 : FrequenciesNumber of days of sick leaveShift(L) Less than 6(M) 6 or MoreTotal(D) Day81220(N) Night121830Total203050Table 4-2: Probablilities Number of days of sick leaveShift(L) Less than 6(M) 6 or MoreTotal(D) Day0.160.240.40(N) Night0.240.360.60Total0.400.601.00Q1 Use Information A to answer this question. Which of the following statements about the values in the table of probabilities is not correct? a. The probability of an employee taking 6 or more days of sick leave P(M) is 0.6 b. The probability that an employee is on the Night Shift (N) and takes less than 6 days of leave (L), is called a conditional probability P(N | L) = 0.6 c. If you know that an employee is on day shift (D) then the probability that they will take less than 6 days of leave (L) is the conditional probability P(L | D) = 0.4 d. The probability that an employee works Day Shift (D) or takes 6 or more days of leave (M) is found using the addition rule to be P(D or M) = 0.76 e. They are all correct Q2 The analyst wishes to use the Probabilities table from Information A to determine whether the work shift variable and the number of days of sick leave variable are or are not independent variables. Which of the following statements about the work shift and the number of days of sick leave variables is correct ? a. These variables are independent because the marginal probabilities such as P(L) are the same as the conditional probabilities P(L | D) b. These variables are not independent because the marginal probability P(L) is different from the conditional probability P(N | L) c. These variables are not independent because the joint probabilities such as P(L and N) are equal to the product of the probabilities P(L).P(N). d. These variables are dependent because the marginal probabilities such as P(L) are equal to the conditional probability P(L | N) e. None of the above Information B, needed to answer Question 3Suppose the manager of a home ware retailer decides in a 5-minute period no more than 4 customers can arrive at a counter. Using past records he obtains the following probability distribution for the possible number of customers who can arrive at a counter.Table 4-3Arrivals (X)01234P(X).15.20.30.20.15Q3 Use Information B to answer this question. If values are rounded to 3 decimal places which of the following is the correct pair of values for the mean, the variance or standard deviation of the number of arrivals at the counter. a. Mean mu = 2 and variance sigma-squared = 1.265 b. Mean mu = 2.5 and variance sigma-squared = 1.6 c. Mean mu = 2 and standard deviation sigma = 1.6 d. Mean mu = 2.4 and variance sigma-squared = 1.6 e. None of the above Information C, needed to answer Questions 4-6The section manager in an insurance company is interested in evaluating how well staff at the inquiry counter handle customer complaints. She interviews a sample of n = 6 customers who have made complaints and asks each of them whether staff had handled their complaints well. Each interview is called a trial. If a customer says their complaint was