Questions and Answers of OpenIntro Statistics

15.33, carry out the analysis of variance calculations and discuss your findings.Can Color Region Red Yellow Blue East 45 50 54 South 49 51 58 Midwest 43 60 50 West 38 49 44
15.50 Refer to Exercise 15.33. Suppose that a second store for each region–can color combination is added to the study, yielding the results shown in the following table. Combining these results
15.49 Refer to Exercise 15.31. Having carried out the experiment to compare mean yields per acre of four varieties of corn and three brands of fertilizer, an agricultural researcher suggested that
15.48 In some experiments with several observations per cell the analyst is prepared to assume that there is no interaction between groups and blocks. Any apparent interaction found is then
15.47 Random samples of two freshmen, two sophomores, two juniors, and two seniors each from four dormitories were asked to rate, on a scale of 1 (poor)to 10 (excellent), the quality of the dormitory
15.46 A researcher randomly collected the annually income(in thousand) in a village for three different age range (less than 20 years old, 20 to 30 years old and above 30 years old) based on gender
15.45 Refer to Exercise 15.44. Twelve pairs were entered in the ice-dancing competition. Once again, there were 9 judges, and contestants were assessed in seven subevents.The sums of squares between
15.44 Suppose that scores given by judges to competitors in the ski-jumping events of the Winter Olympics were analyzed. For the men’s ski-jumping competition, suppose there were 22 contestants and
15.43 Consider an experiment with treatment factors A and B, with factor A having three levels and factor B having seven levels. The results of the experiment are summarized in the following analysis
15.42 The partial output for an experiment with treatment factors A and B are summarized in the following table.Source of Variation Sum of Squares Degrees of Freedom Degrees of Freedom Treatment A
15.41 Consider an experiment with treatment factors A and B, with factor A having four levels and factor B having three levels. The results of the experiment are summarized in the following analysis
15.40 Suppose that, in the two-way analysis of variance setup with one observation per cell, there are just two groups. Show in this case that the F ratio for testing the equality of the group
15.39 Three television pilots for potential situation-comedy series were shown to audiences in four regions of the country—the East, the South, the Midwest, and the West Coast. Based on audience
15.38 Four brands of fertilizer were evaluated. Each brand was applied to each six plots of land containing soils of different types. Percentage increases in corn yields were then measured for the 24
15.37 Four real estate agents were asked to appraise the values of 10 houses in a particular neighborhood. The appraisals were expressed in thousands of dollars, with the results shown in the
15.36 For the data of Exercise 15.34, obtain sample estimates for each term on the right-hand side of the equation used in the previous exercise for the text C–multiple choice combination.
15.35 We introduced for the two-way analysis of variance the population model Xij - m = Gi + bj + eij For the data of Exercise 15.33, obtain sample estimates for each term on the right-hand side of
15.34 An instructor in an economics class is considering three different texts. He is also considering three types of examinations—multiple choice, essay, and a mix of multiple choice and essay
15.33 A diet soda manufacturer wants to compare the effects on sales of three can colors—red, yellow, and blue. Four regions are selected for the test, and three stores are randomly chosen from
15.32 A company has test-marketed three new types of soup in selected stores over a period of 1 year. The following table records sales achieved (in thousands of dollars) for each of the three soups
15.31 In Greece, an agricultural experiment designed to assess differences in yields of olives for four different varieties (Athenolia, Black olives, Green olives, and Koroneiki), using six different
15.30 Four financial analysts were asked to predict earnings growth over the coming year for five oil companies.Their forecasts, as projected percentage increases in earnings, are given in the
15.29 Consider a two-way analysis of variance with one observation per cell and randomized blocks with the following results:Source of Variation Sum of Squares Degrees of Freedom Between groups 131 3
15.28 Consider a two-way analysis of variance with one observation per cell and randomized blocks with the following results:Source of Variation Sum of Squares Degrees of Freedom Between groups 380 6
15.27 Consider a two-way analysis of variance with one observation per cell and randomized blocks with the following results:Source of Variation Sum of Squares Degrees of Freedom Between groups 3636
15.26 A pharmacist randomly selected a group of 45 individuals with a similar level of back pain. The participants randomly distributed into three treatment groups in which using three different
15.25 Based on the data of Exercise 15.11, perform the Kruskal-Wallis test of the null hypothesis of equal population mean scores on the CPA exam for students using no tutoring services and using
15.24 Refer to Exercise 15.10. Without assuming normal population distributions, test the null hypothesis that the population mean times spent outside the classroom on teaching responsibilities are
15.23 Based on the data of Exercise 15.9, use the Kruskal-Wallis method to test the null hypothesis of equality of growth predictions for population mean sales for the four regions.
15.22 Using the data of Exercise 15.8, carry out a nonparametric test of the null hypothesis of equality of population mean examination scores for freshmen, sophomores, and juniors.
15.21 For the data of Exercise 15.7, test the null hypothesis that the population mean operating costs per mile are the same for all three types of cards without assuming normal population
15.20 Using the data of Exercise 15.6, carry out a test of the null hypothesis of equality of the three population mean numbers of parts per shipment not conforming to standards without assuming
15.19 Using the data of Exercise 15.5, perform a Kruskal-Wallis test of the null hypothesis that the population mean test scores are the same for students assigned to the four teaching assistants.
15.18 For the data of Exercise 15.4, use the Kruskal-Wallis test of the null hypothesis that the population mean sales levels are identical for three box colors.
15.17 Consider a problem with four subgroups with the sum of ranks in each of the subgroups equal to 227, 151, 198, and 271 and with subgroup sizes equal to 5, 9, 15, and 12. Complete the
15.16 Consider a problem with three subgroups with the ranks in each subgroup shown as follows. Complete the Kruskal-Wallis test and test the null hypothesis to determine whether the subgroups have
15.15 Consider a problem with three subgroups with different subgroup sizes of n1 = 8, n2 = 7, and n3 = 6.The sum of ranks in each of these subgroups equal to 131, 58, and 42. Complete the
15.14 Use the model for the one-way analysis of variance for the data of Exercise 15.12.a. Estimate m.b. Estimate Gi for each of the three magazines.c. Estimate e13, the error term corresponding to
15.13 Independent random samples of 6 advertisements were taken from three different magazines: EuroScientist, Focus, and Science Reporter. The fog indices, measuring the reading difficulty of a
15.12 In the study of Example 15.1, independent random samples of six advertisements from True Confessions, People Weekly, and Newsweek were taken. The fog indices for these advertisements are given
15.5 An instructor at the University of Liège, Belgium, teaches a class of 28 students. At the beginning of the semester, each student is randomly assigned to one of four teaching
15.4 A manufacturer of cereal is considering three alternative box colors—red, yellow, and blue. To check whether such a consideration has any effect on sales, 16 stores of approximately equal size
15.3 Given the information in the following table, compute the F ratio and test the hypothesis that the group means are equal. The SST = 378.Group 1 Group 2 Group 3 Size, ni 18 12 13 Mean, xi 2.1 6.4
15.2 Given the following analysis of variance table, compute mean squares for between groups and within groups. Compute the F ratio and test the hypothesis that the group means are equal.Source of
15.1 Given the following analysis of variance table, compute mean squares for between groups and within groups. Compute the F ratio and test the hypothesis that the group means are equal.Source of
15.5 Two-Way Analysis of Variance: More Than One Observation per Cell
15.4 Two-Way Analysis of Variance: One Observation per Cell, Randomized Blocks
15.3 The Kruskal-Wallis Test
15.2 One-Way Analysis of Variance Multiple Comparisons Between Subgroup Means Population Model for One-Way Analysis of Variance
15.1 Comparison of Several Population Means
14.79 Suppose that a random sample of 513 individuals were randomly sampled and information was collected about the method a subject used to make an airline reservation (last reservation for either
14.78 Nine pairs of hypothetical profiles were constructed for corporate employees applying for admission to an executive MBA program. Within each pair, these profiles were identical, except that one
14.77 A random sample of 10 corporate analysts was asked to rate, on a scale from 1 (very poor) to 10 (very high), the prospects for their own corporations and for the economy at large in the current
14.76 Of a random sample of 150 clerks, 65 estimated to spend no more than €10 per meal, 48 estimated to spend more than €10 per meal, and 37 estimated to spend exactly €10 per meal. Evaluate
14.75 The suggested queuing time in a fast-food restaurant is 10 minutes. Of a random sample of 50 customers, 8 expected to be in queue for more than 10 minutes, 27 expected to be in queue for less
14.74 In a random sample of 15 people participating in a weight loss program, 10 believe they will experience significant weight loss, 3 think their weight will remain the same, and the remaining
14.73 The qualifying percentage for a midterm test at a particular school is 50%. After the test, out of 20 sampled students, 2 students believed that they would fail the test, 15 believed that they
14.72 What is nonparametric test? State two reasons for using such tests.
14.71 In Example 14.2 a random sample of 200 people was asked to indicate candy bar preference. Suppose that we also gathered demographic data such as whether the participants were male or female.
14.70 Two years ago the manager of a local supermarket that sells three national brands (brands A, B, and C) and one store brand (brand D) of orange juice found that brands A and C were equally
14.69 Downsizing is one method companies may use in an attempt to reduce costs. Suppose that the following contingency table shows the number of layoffs in three manufacturing plants during the last
14.68 Many easy-weight-loss products are just gimmicks that attract people with the hope of a fast way to a slimmer body. Suppose that a random sample of residents in one community was asked if they
14.67 Should large retailers offer banking services? Small community banks may be concerned about their future if more retailers enter the world of banking.Suppose that a market research company
14.66 Suppose that a random sample of businesses that relocated in Florida within the last 3 years is surveyed.Do the data in the following contingency table show any relationship between the primary
14.65 A random sample of companies was surveyed and asked to indicate if they had used an Internet career service site to search for prospective employees. The companies were also asked questions
14.64 Suppose the operations manager at a Honda service center conducts a survey on the level of satisfaction for the quality of workmanship based on the customer’s gender. A random sample of 200
14.63 A travel agent randomly sampled individuals in her target market and asked, Did you use a travel agent to book your last airline flight? By cross-referencing the answers to this question with
14.62 The Speedi-Flex delivery service is conducting a study of its delivery operations. As part of this study it collected data on package type by originating source for one day’s operation for
14.61 Aurica Sabou has been working on a plan for new store locations as part of her regional expansion. In the city proposed for expansion there are three possible locations: north, east, and west.
14.60 The gear-cutting department in a large manufacturing firm produces high-quality gears. The number produced per hour by a single machinist is 1, 2, or 3, as shown in the table. Company
14.59 A manufacturer of household appliances wanted to determine if there was a relationship between family size and the size of washing machines purchased by customers. The manufacturer was
14.58 Sally Smith is a long-time political campaign manager from Chicago. In the primary election there are four candidates. She wishes to determine if voter preference is different over the four
14.57 A doctor is analyzing the infection rate of a particular kind of disease in Asia and Europe. Perform a chi-square test to determine if there is a different probability of infection between the
14.56 An officer of a jobseekers’ website in analyzing the employment trends of university students for three different majors of Marketing, Finance, and Economic. The officer would like to know
14.55 An analyst conducted a survey and found that the respondents can be categorized into three broad categories professionals, speeders, and posers by three age groups of Group 1: 21 to 30 years,
14.54 A researcher is analyzing the marital status of the employees(Single, Married, Divorced, and Widowed)that are working in the three different departments(Marketing, Purchasing, and Finance). The
14.51 On October 18, 2018, the fuel prices in Portugal went down after having risen to a five-year high the previous week. The Fuel Prices data file contains the price per liter of gasoline and of
14.50 The Tesla Stock Prices data file shows the closing price of Tesla’s stocks in the first day of each month for a period of 12 consecutive months. Test for randomness using the runs test.
14.49 The data file Brent Oil Price contains the monthly oil prices for Brent crude oil, covering the years 2012 to 2020.a. Plot the time series of the crude oil price for the year 2012. Perform a
14.48 The data file Euribor 12 Months shows an average annual interest rate of certain European banks over 18 consecutive years. Use the runs test to test this series for randomness.
14.47 Use the runs test to test for randomness the number of miles traveled per week for a car in three months.Week Distance (miles) Week Distance (miles)1 253 7 450 2 452 8 678 3 308 9 529 4 414 10
14.46 A time series contains 50 observations. What is the probability that the number of runs isa. no more than 13?b. fewer than 15?c. greater than 34?
14.45 A time series contains 10 and 16 observations. Determine the probability of the number of runs for the following.a. n = 10, P(R 7 5)b. n = 16, P(4 6 R 6 7)
14.44 Given a sequence 0.16, 0.27, 0.58, 0.63, 0.45, 0.21, 0.72, 0.87, 0.27, 0.15, 0.92, 0.85.a. How many runs for the sequence in total?b. What is the probability the number of run is less than 6?
14.43 The accompanying table shows, for a random sample of 20 long-term-growth mutual funds, percentage return over a period of 12 months and total assets (in millions of pounds).Return Assets Return
14.42 Petron has formulated a new chemical to be added in their petrol. To determine the effectiveness of the new formulated chemical, they recorded the amount of chemical had been added in the
14.41 An investment company is going to make decision on which mobile app they are to invest from two different mobile application developments. The company accesses the ability on the two apps by
14.40 JW Intelligent proposed a new moisturizing cream that includes herbal essence as a key ingredient. A random sample of 15 women were selected for a pilot trial of the new product. The women used
14.39 A newsletter rates mutual funds. Independent random samples of 12 funds with the highest rating and 12 funds with the lowest rating were chosen. The following figures are percentage rates of
14.38 Two different drugs for deliberating headaches are being analyzed for effectiveness. The analyst uses a random selection of 15 patients to test the first drug and 13 patients for the second
14.37 GreenEnergy, a manufacturing company in Finland, wants to know the consumer satisfaction level for two products—A and B. A random sample of 12 consumers are invited to participate in a
14.36 The human resources department of Alfa Laval, Sweden, is analyzing on the number of years of work experience of employees in the marketing and finance departments. For a random sample of 12
14.34 A study compared firms with and without an audit committee. For samples of firms of each type, the extent of directors’ ownership was measured using the number of shares owned by the board as
14.33 A random sample of 80 owners of videocassette recorders was taken. Each sample member was asked to assess the amounts of time in a month spent watching material he or she had recorded from
14.32 A consultant is interested in the impact of the introduction of a total-quality management program on job satisfaction of employees. A random sample of 30 employees was asked to assess level of
14.31 A random sample of 40 business majors who had just completed introductory courses in both statistics and accounting was asked to rate each class in terms of level of interest on a scale of 1
14.30 Sixteen freshmen on a college campus were grouped into eight pairs in such a way that the two members of any pair were as similar as possible in academic backgrounds—as measured by high
14.29 A random sample of 10 students was asked to rate, in a blind taste test, the quality of two brands of ice cream, one reduced-sugar and one regular ice cream. Ratings were based on a scale of 1
14.28 A random sample of 160 shoppers was asked to compare two new energy bars. From the sample, 91 shoppers preferred energy bar A, 61 preferred energy bar B, and 8 expressed no preference. Use the
14.27 A random sample of 60 professional economists was asked to predict whether next year’s inflation rate would be higher than, lower than, or about the same as that in the current year. The

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