Question: When a real data set is normally

> Suppose you learn that the p- value for a hypothesis test is equal to 0.0217. What can you say about the result of this test?

> What standard error would you use to test whether a new observation came from the same population as a sample? (Give both its name and the formula.)

> Suppose you have an estimator and would like to test whether or not the population mean value equals 0. What do you need in addition to the estimated value?

> What p-value statement is associated with each of the following outcomes of a hypothesis test? a. Not significant. b. Significant. c. Highly significant. d. Very highly significant.

> a. What confidence levels other than 95% are in common use? b. What would you do differently to compute a 99% confidence interval instead of a 95% interval? c. Which is larger, a two-sided 90% confidence interval or a two-sided 95% confidence interval?

> Why are critical t values generally larger than1.960 for a two-sided 95% confidence interval?

> Why is it correct to say, “We are 95% sure that the population mean is between $15.85 and $19.36” but not proper to say, “The probability is 0.95 that the population mean is between $15.85 and $19.36”?

> Which fact about a normal distribution leads to the factor 2 (or 1.960) in the approximate confidence interval statement?

> What does a confidence interval tell you about the population that an estimated value alone does not?

> Do exercise 3 using the ages instead of the salaries. Data from exercise 3: Continuing with the sample from the preceding exercise: a. Find the population mean for salary. (Note: In real life, you usually cannot find the population mean. We are peeking

> In what way do bivariate data represent more than just two separate univariate data sets?

> In what important way does statistical inference go beyond summarizing the data?

> a. What is the sampling distribution of a statistic? b. What is the standard deviation of a statistic?

> a. What is a statistic? b. What is a parameter?

> What is a frame? What is its role in sampling?

> What do the standard errors Sx and Sp indicate for a binomial situation?

> a. What is the complement of an event? b. What is the probability of the complement of an event?

> What are mutually exclusive events?

> a. What is an event? b. Can a random experiment have more than one event of interest?

> a. What is an outcome? b. Must the outcome be a number?

> Do exercise 2 using the experiences instead of the salaries. Data from exercise 2: Draw a random sample without replacement of 10 employees, using the table of random digits, starting in row 23, column 7. a.* List the employee numbers for your sample.

> a. What is a sample space? b. Is there anything random or uncertain about a sample space?

> What is the design phase of a statistical study?

> What is a joint probability table?

> a. What is the coefficient of variation? b. What are the measurement units of the coefficient of variation?

> If your data set is normally distributed, what proportion of the individuals do you expect to find: a. Within one standard deviation from the average? b. Within two standard deviations from the average? c. Within three standard deviations from the averag

> a. What is a deviation from the average? b. What is the average of all of the deviations?

> a. What is the traditional measure of variability? b. What other measures are also used?

> When a fixed number is added to each data value, what happens to a. The average, median, and mode? b. The standard deviation and range? c. The coefficient of variation?

> Which variability measure is most useful for comparing variability in two different situations, adjusting for the fact that the situations have very different average sizes? Justify your choice.

> What is variability?

> Do exercise 2 using the ages instead of the salaries. Data from exercise 2: Draw a random sample without replacement of 10 employees, using the table of random digits, starting in row 23, column 7. a.* List the employee numbers for your sample. b. Find

> What is the mode?

> How do you find the median for a data set: a. With an odd number of values? b. With an even number of values?

> What is statistics?

> What is the median? How can it be found from its rank?

> What is meant by a typical value for a list of numbers? Name three different ways of finding one.

> How should you deal with exceptions when summarizing a set of data?

> What is a box plot? What additional detail is often included in a box plot?

> What is the five-number summary?

> What are the quartiles?

> Name two ways in which percentiles are used.

> Continuing with the sample from the preceding exercise: a. Find the population mean for salary. (Note: In real life, you usually cannot find the population mean. We are peeking “behind the scenes” here.) b. Compare this population mean to the sample aver

> Which summary measure is best for a. A normal distribution? b. Projecting total amounts? c. A skewed distribution when totals are not important?

> Which summary measure(s) may be used on a. Nominal data? b. Ordinal data? c. Quantitative data?

> What is summarization of a data set? Why is it important?

> How should statistical analysis and business experience interact with each other?

> What is a skewed distribution?

> Are all data sets normally distributed?

> Why is the normal distribution important in statistics?

> What is a normal distribution?

> What is a number line?

> Draw a random sample without replacement of 10 employees, using the table of random digits, starting in row 23, column 7. a.* List the employee numbers for your sample. b. Find the average salary for yours sample and interpret this number. c. Find the st

> Suppose there is an outlier in your data. You plan to analyze the data twice: once with and once without the outlier. What result would you be most pleased with? Why?

> When is it appropriate to set aside an outlier and analyze only the rest of the data?

> What is an outlier?

> How can you interpret the logarithm of a number?

> What is a variable?

> What is a list of numbers?

> What is the difference between quantitative and qualitative data?

> What is an elementary unit?

> What are qualitative data?

> Distinguish between an observational study and an experiment.

> Continue to view this database as the sample space as in database exercise 1. a. Are the two events “training level A” and “training level B” independent? How do you know? b. Are the two events “training level A” and “training level B” mutually exclusive

> A consultant has just presented a very complicated statistical analysis, complete with lots of mathematical symbols and equations. The results of this impressive analysis go against your intuition and experience. What should you do?

> Differentiate between time-series data and cross sectional data.

> What distinguishes data mining from other statistical methods? What methods, in addition to those of statistics, are often used in data mining?

> What is a data set?

> Why is a confidence interval more useful than an estimated value?

> Why is it worth the effort to learn about statistics? a. Please answer for management in general. b. Please answer for one particular area of business of special interest to you.

> Classify a data set found on the Internet consisting of sales, profits, and number of employees for 100 banking firms. Be sure to provide standard information about the number of variables, who controlled the design of the data-gathering plan, and whethe

> For each of the following data sets, say whether it is primary or secondary data. a. U.S. government data on recent economic activity, by state, being used by a company planning to expand. b. Production-cost data on recent items produced at your firm’s f

> Your firm has decided to sue an unreliable supplier. What kind of analysis would be used to estimate the forgone profit opportunities based on the performance of competitors, the overall state of the economy, and the time of year?

> Which of the five basic activities of statistics is represented by each of the following situations? a. A factory’s quality control division is examining detailed quantitative information about recent productivity in order to identify possible trouble sp

> Continue to view this database as the sample space as in databaseexercise1.Consider the two events“ high experience (6 years or more)” and “female.” a. Find the probabilities of these two events. b. Find the probability of their intersection. What does t

> Consider the histogram in Fig. 3.8.5, which indicates performance of recent on-site service contracts as a rate of return. a. At the very high end, how many contracts were extreme outliers that earned over 900% per year? b. How many contracts are outlier

> What distribution shape is represented by the histogram in Fig. 3.8.4 of hospital length of stay (in days)? Fig. 3.8.4: 20 10 - 0- 10 20 30 40 Days

> What distribution shape is represented by the histogram in Fig. 3.8.3 of volume (in thousands of units) by sales region? Fig. 3.8.3: 40 30 10 10 20 30 40 50 60 70 Volume 20

> What distribution shape is represented by the histogram in Fig. 3.8.2 of profit margins for consumer products? Fig. 3.8.2: 50 40 30 20 10 10 15 20 25 30 Percent 5.

> Your firm’s sales, listed each quarter for the past 5 years, should be helpful for strategic planning. a. Is this data set cross-sectional or time-series? b. Is this univariate, bivariate, or multivariate data?

> In order to figure out how much of the advertising budget to spend on various types of media (TV, radio, newspapers, etc.), you are looking at a data set that lists how much each of your competitors spent last year for TV, how much they spent for radio,

> Table2.6.4 is an excerpt from a sales person’s database of customers. a. What is an elementary unit for this data set? b. What kind of data set is this: Univariate, bivariate, or multivariate? c. Which of these variables are quantitativ

> Table 2.6.3 consists of sales and income, both in hundred thousands of dollars, for a 6-month period. a. What is an elementary unit for this data set? b. What kind of data set is this: Univariate, bivariate, or multivariate? c. Which of these two variabl

> Consider the data set in Table 2.6.2, which consists of observations on five production facilities (identified by their group ID). a. What is an elementary unit for this data set? b. What kind of data set is this: Univariate, bivariate, or multivariate?

> Your company is trying to estimate the total size of its potential market. A survey has been designed, and data have been collected. A histogram of the data shows a small amount of skewness. Which summary measure would you recommend to the company for th

> Please view this database as the sample space of a random experiment in which an employee is selected at random. That is, each employee represents one outcome, and all possible outcomes are equally likely. a.* Find the probability of selecting a female e

> If you think about a telephone directory as a large data set, what are the elementary units?

> What distribution shape is represented by the histogram in Fig. 3.8.1 of voltages measured for incoming components as part of a quality control program? Fig. 3.8.1: 25 20 15 10 5. 100 102 104 106 108 110 112 Volts

> Table 15.5.4 shows the average quality scores for production, averaged according to which supplier (A, B, or C) provided the materials and which shift (day, night, or swing) was active at the time the part was produced; this is followed by the computer v

> Refer to the data for problem 11. Continue using the logarithms of the lengths of calls. a. Find the total sample size, n, the grand average,

> Which time-series method of analysis would be most appropriate to a situation in which prices are lower at harvest time in the fall but are typically higher the rest of the year and in which there is a need for a methodology that is relatively easy to un

> Which time-series method of analysis would be most appropriate to a situation in which forecasts and confidence limits are needed for a data set that shows medium-term cyclic behavior?

> A bank had 38,091 ATM network transactions at its cash machines in January and had 43,182 in February. The seasonal indices are 0.925 for January and 0.986 for February. a. By what percent did ATM transactions increase from January to February? b. By wha

> You have suspected for some time that production problems tend to flare up in the wintertime, during the first quarter of each year. A trend-seasonal analysis of the defect rates indicates seasonal indices of 1.00, 1.01, 1.03, and 0.97 for quarters 1, 2,

> Your seasonally adjusted monthly sales forecast is $382,190+$4,011 (Month number), where the month number is 1 for Jan. 2011 and increases by 1 each month. The seasonal index for February sales is 0.923, and it is 1.137 for April. What you need now is a

> Which type of time-series analysis would provide the simplest results for studying demand for heating oil, which tends to be highest in the winter?

> For the experience variable: Answer the parts of exercise 2. Data from exercise 2: For the annual salary levels: a. Construct a histogram and indicate the average and standard deviation. b. How many employees are within one standard deviation from the

> For each of the following, tell whether or not you would expect it to have a strong seasonal component and why. a. Sales of colorful wrapping paper, recorded monthly. b. The number of air travelers to Hawaii from Chicago, recorded monthly. c. The S&P 500

> For each of the following sentences, say which section (or sections) it might be located in. a.* The scatterplot of defects against the rate of production shows a moderately strong relationship, withacorrelationof0.782, suggesting that our worst problems

> Using your imagination, create an executive summary paragraph for a hypothetical report based on each of the situations in problem 1. (Note: Only one paragraph is required for each situation.) Data from problem 1: Your boss has just asked you to write