| № |
Condition |
free/or 0.5$ |
| m102925 | Which of the following sampling procedures involve the use of probability sampling?
a. A college student is hired to interview a sample of voters in her town. She stays on campus and interviews 100 students in the cafeteria.
b. A pollster wants to interview 20 gas station managers in Baltimore. He posts a list of all such managers on his wall, closes his eyes, and tosses a dart at the list 20 times. He interviews the people whose names the dart hits. |
buy |
| m102926 | Which parametric tests do the following tests replace?
(a) Sign test
(b) Wilcoxon signed-ranks T test
(c) Mann-Whitney U test
(d) Kruskal-Wallis H test
(e) Friedman test |
buy |
| m102927 | Which technique for gathering data (observational study or experiment) do you think was used in the following studies? Explain.
(a) The U.S. Census Bureau tracks population age. In 1900, the percentage of the population that was 19 years old or younger was 44.4%. In 1930, the percentage was 38.8%; in 1970, the percentage was 37.9%; and in 2000, the percentage in that age group was down to 28.5% (Reference: The First Measured Century, T. Caplow, L. Hicks, and B. J. Wattenberg).
(b) After receiving the same lessons, a class of 100 students was randomly divided into two groups of 50 each. One group was given a multiple-choice exam covering the material in the lessons. The other group was given an essay exam. The average test scores for the two groups were then compared. |
buy |
| m102928 | Which type of income statement-single-step or multiple-step-does The North West Company use? You can find its financial statements in Appendix A at the back of this textbook. |
buy |
| m102929 | Why are the degrees of freedom for the t distribution and the degrees of freedom for sample variance the same? |
buy |
| m102930 | Why do two normal distributions that have equal standard deviations have the same shape? |
buy |
| m102931 | Why is obtaining the mean and standard deviation of x̅ a first step in approximating the sampling distribution of the sample mean by a normal distribution? |
buy |
| m102932 | Why is the basic counting rule (BCR) often referred to as the multiplication rule? |
buy |
| m102933 | Why is the phrase "goodness of fit" used to describe the type of hypothesis test considered in this section? |
buy |
| m102934 | Why is the variance not meaningful to analyze ordinal scale data? |
buy |
| m102935 | Why should you generally expect some error when estimating a parameter (e.g., a population mean) by a statistic (e.g., a sample mean)? What is this kind of error called? |
buy |
| m102936 | Wild irises are beautiful flowers found throughout the United States, Canada, and northern Europe. This problem concerns the length of the sepal (leaf-like part covering the flower) of different species of wild iris. Data are based on information taken from an article by R. A. Fisher in Annals of Eugenics (Vol. 7, part 2, pp. 179-188). Measurements of sepal length in centimeters from random samples of Iris setosa (I), Iris versicolor (II), and Iris virginica (III) are as follows:
Shall we reject or not reject the claim that there are no differences among the population means of sepal length for the different species of iris? Use a 5% level of signifi cance?
In the problem, please provide the following information.
(a) What is the level of signifi cance? State the null and alternate hypotheses.
(b) Find SSTOT, SSBET, and SSW and check that SSTOT - SSBET + SSW. Find d.f.BET, d.f.W, MSBET, and MSW. Find the value of the sample test statistic F (F ratio).
What are the degrees of freedom?
(c) Find (or estimate) the P-value of the sample test statistic.
(d) Based on your answers in parts (a) to (c), will you reject or fail to reject the null hypothesis?
(e) Interpret your conclusion in the context of the application.
(f) Make a summary table for your ANOVA test. |
buy |
| m102937 | Wildfires are uncontrolled fires that usually spread quickly and are common in wilderness areas that have long and dry summers. The National Interagency Fire Center reports statistics on wildfires on their website www.nifc.gov. The following data lists the size, in thousands of acres, of a sample of 14 large (at least 100,000 acres) wildfires.
Use the technology of your choice to decide whether applying the one-mean t-interval procedure to these data is reasonable. Justify your answer. |
buy |
| m102938 | Wilfley and colleagues (2008) tested whether the antiobesity drug sibutramine would be an effective treatment for people with binge eating disorder. They measured the frequency of binge eating every 2 weeks for 24 weeks during treatment. The following table lists a portion of the data similar to results reported by the authors for the frequency of binge eating over the first 8 weeks of the drug treatment.
(a) Complete the F table and make a decision to retain or reject the null hypothesis.
(b) Use the Bonferroni procedure to make the post hoc test. In which week do we first see significant differences compared to baseline? |
buy |
| m102939 | Wind Mountain is an archaeological study area located in southwestern New Mexico. Pot sherds are broken pieces of prehistoric Native American clay vessels. One type of painted ceramic vessel is called Mimbres classic black-on-white. At three different sites, the number of such sherds was counted in local dwelling excavations (Source: Based on information from Mimbres Mogollon Archaeology by A. I. Woosley and A. J. McIntyre, University of New Mexico Press).
Shall we reject or not reject the claim that there is no difference in population mean Mimbres classic black-on-white sherd counts for the three sites? Use a 1% level of significance.
In the problem, please provide the following information.
(a) What is the level of signifi cance? State the null and alternate hypotheses.
(b) Find SSTOT, SSBET, and SSW and check that SSTOT - SSBET + SSW. Find d.f.BET, d.f.W, MSBET, and MSW. Find the value of the sample test statistic F (F ratio).
What are the degrees of freedom?
(c) Find (or estimate) the P-value of the sample test statistic.
(d) Based on your answers in parts (a) to (c), will you reject or fail to reject the null hypothesis?
(e) Interpret your conclusion in the context of the application.
(f) Make a summary table for your ANOVA test. |
buy |
| m102940 | Wing Foot is a shoe franchise commonly found in shopping centers across the United States. Wing Foot knows that its stores will not show a pro fit unless they gross over $940,000 per year. Let A be the event that a new Wing Foot store grosses over $940,000 its first year. Let B be the event that a store grosses over $940,000 its second year. Wing Foot has an administrative policy of closing a new store if it does not show a pro fit in either of the fi rst 2 years. The accounting of fice at Wing Foot provided the following information: 65% of all Wing Foot stores show a pro fit the fi rst year; 71% of all Wing Foot stores show a pro fit the second year (this includes stores that did not show a profi t the fi rst year); however, 87% of Wing Foot stores that showed a pro fit the fi rst year also showed a pro fit the second year. Compute the following:
(a) P (A)
(b) P (B)
(c) P (B | A)
(d) P (A and B)
(e) P (A or B)
(f) What is the probability that a new Wing Foot store will not be closed after 2 years? What is the probability that a new Wing Foot store will be closed after 2 years? |
buy |
| m102941 | With an ever-increasing world population, grain yields are extremely important. A random sample of 16 large grain producing regions in the world gave the following information about grain production (in kg/hectare)
Does this information indicate that modern grain production is higher? Use a 5% level of signifi cance.
(a) What is the level of signi ficance? State the null and alternate hypotheses.
(b) Compute the sample test statistic. What is the sampling distribution?
(c) Find the P-value of the sample test statistic.
(d) Conclude the test.
(e) Interpret the conclusion in the context of the application. |
buy |
| m102942 | With regard to the use of a Poisson distribution to approximate binomial probabilities, on page 254 we stated that "As you might expect, the appropriate Poisson distribution is the one whose mean is the same as that of the binomial distribution. . . ." Explain why you might expect this result. |
buy |
| m102943 | Without consulting Table II, explain why the area under the standard normal curve that lies to the right of 0 is 0.5? |
buy |
| m102944 | Witt and Schrodt (2006) tested the relationship between nonverbal immediacy (behaviors that enhance closeness and nonverbal interaction with others) and technology. They tested whether teacher nonverbal immediacy (high, low) in classes with different levels of technology use (none, minimal, moderate, complete) would influence student perceptions of the teacher. They computed a 4 × 2 ANOVA to analyze the data. The table lists the cell means at each level of the two factors.
(a) Graph the cell means.
(b) Is a possible interaction evident? Explain. |
buy |