For independent samples, the graphs are for the two samples; for a paired sample, the graphs are for the paired differences. The intent is to employ the sample data to perform a hypothesis test to compare the means of the two populations from which the data were obtained. In each case, decide which, if any, of the procedures that you have studied should be applied.
Paired; n = 75
> The U.S. Census Bureau compiles information on money income of people by type of residence and publishes its finding in Current Population Reports. Independent simple random samples of people residing inside principal cities (IPC), outside principal citi
> Regarding a χ2-curve: a. At what point on the horizontal axis does the curve begin? b. Classify its shape as symmetric, left skewed, or right skewed. c. As the number of degrees of freedom increases, a χ2-curve begins to look like another type of curve.
> In the article “Happier and Less Isolated: Internet Use in Old Age” (Journal of Poverty & Social Justice, Vol. 21, Issue 1, pp. 33–45), researcher O. Lelkes explores the impact of Internet use. The following problem is based on the article. A random samp
> Refer to Problems 15–17. a. What percentage of hospitals are under proprietary control? b. What percentage of psychiatric hospitals are under proprietary control? c. What percentage of hospitals are psychiatric hospitals? d. What percentage of hospitals
> Refer to Problems 15 and 16. a. In view of your answer to Problem 16(b), without doing any further calculations, respond true or false to the following statement and explain your answer: “The conditional distributions of facility type within control type
> Refer to Problem 15. a. Obtain the conditional distribution of control type within each facility type. b. Does an association exist between facility type and control type? Explain your answer. c. Find the marginal distribution of control type. d. Constru
> From data in Hospital Statistics, published by the American Hospital Association, we obtained the following contingency table for U.S. hospitals and nursing homes by type of facility and type of control. We used the abbreviations Gov for Government, Prop
> Refer to Problem 12. a. Find the conditional distributions of birth region by party and the marginal distribution of birth region. b. Does an association exist between the variables “birth region” and “party” for the U.S. presidents? Explain your answer.
> Refer to Problem 12. a. Find the conditional distributions of party by birth region and the marginal distribution of party. b. Does an association exist between the variables “birth region” and “party” for the U.S. presidents? Explain your answer. c. Wha
> We have presented some quantitative data sets and specified a grouping method for practicing the concepts. For each data set, a. determine a frequency distribution. b. obtain a relative-frequency distribution. c. construct a frequency histogram based on
> In its Summer 2013 Animal Action Report, the National Anti-Vivisection Society stated that “59% of Americans between the ages of 18 and 29 oppose medical testing on animals.” The percentage of 59% was computed from sample data. a. Identify the population
> From the Information Please Almanac, we compiled the following table on U.S. region of birth and political party of the first 44 U.S. presidents. The table uses these abbreviations: F = Federalist, DR = Democratic-Republican, D = Democratic, W = Whig, R
> The U.S. Census Bureau compiles census data on educational attainment of Americans. From the document Current Population Survey, we obtained the 2010 distribution of educational attainment for U.S. adults 25 years old and older. Here is that distribution
> Consider a χ2-curve with 17 degrees of freedom. Use Table V to determine a. χ20.10. b. χ20.01. c. the χ2-value that has area 0.05 to its right.
> How do you distinguish among the infinitely many different chi-square distributions and their corresponding χ2-curves?
> The National Association of Colleges and Employers sponsors the Graduating Student and Alumni Survey. Part of the survey gauges student optimism in landing a job after graduation. According to one year’s survey results, published in American Demographics
> ABCNEWS.com published the results of a poll that asked U.S. adults whether they would get a smallpox shot if it were available. Sampling, data collection, and tabulation were done by TNS Intersearch of Horsham, Pennsylvania. When the risk of the vaccine
> Suppose that you are using independent samples to compare two population proportions. Fill in the blanks. a. The mean of all possible differences between the two sample proportions equals the . b. For large samples, the possible differences between the t
> A poll was conducted by Opinion Research Corporation to estimate the proportions of men and women who get the “holiday blues.” Identify the a. specified attribute. b. two populations. c. two population proportions. d. two sample proportions. e. According
> What does the margin of error for the estimate of a population proportion tell you?
> Fill in the blanks. a. The mean of all possible sample proportions is equal to the ___? b. For large samples, the possible sample proportions have approximately a distribution. c. A rule of thumb for using a normal distribution to approximate the distrib
> We have presented some quantitative data sets and specified a grouping method for practicing the concepts. For each data set, a. determine a frequency distribution. b. obtain a relative-frequency distribution. c. construct a frequency histogram based on
> Explain what each phrase means in the context of inferences for a population proportion. a. Number of successes b. Number of failures
> Why is a sample proportion generally used to estimate a population proportion instead of obtaining the population proportion directly?
> In the New York Times article “A Common Police Vest Fails the Bulletproof Test,” E. Lichtblau reported on a U.S. Department of Justice study of 103 bulletproof vests containing a fiber known as Zylon. In ballistics tests, only 4 of these vests produced a
> Refer to Problem 13. a. Find a 99% confidence interval for the difference, p1 − p2, between the proportions of men and women smartphone owners. b. Interpret your answer in part (a) in terms of the difference in percentages of men and women smartphone own
> The Pew Internet & American Life Project conducted a survey of smartphone ownership. One aspect of the study involved the gender of smartphone owners. Of 1029 sampled men, 607 owned a smartphone; and of 1223 sampled women, 648 owned a smartphone. At the
> In the article “Height and Weight at Various Ages and Risk of Breast Cancer” (Annals of Epidemiology, Vol. 2, pp. 597–609), L. Brinton and C. Swanson discussed the relationship between height and breast cancer. The study, sponsored by the National Cancer
> In an issue of Parade Magazine, the editors reported on a national survey on law and order. One question asked of the 2512 U.S. adults who took part was whether they believed that juries “almost always” convict the guilty and free the innocent. Only 578
> Refer to Problem 9. a. Determine a sample size that will ensure a margin of error of at most 0.02 for a 95% confidence interval without making a guess for the observed value of p^. b. Find a 95% confidence interval for p if, for a sample of the size dete
> An international poll of physicians was conducted on the New England Journal of Medicine website asking “Do you believe that the overall medicinal benefits of marijuana outweigh the risks and potential harms?” Identify the: a. specified attribute. b. pop
> Find a 98% confidence interval for the difference between the mean litter sizes of cottonmouths in Florida and Virginia. Interpret your result.
> We have presented some quantitative data sets and specified a grouping method for practicing the concepts. For each data set, a. determine a frequency distribution. b. obtain a relative-frequency distribution. c. construct a frequency histogram based on
> In the article “The Eastern Cottonmouth (Agkistrodon piscivorus) at the Northern Edge of Its Range” (Journal of Herpetology, Vol. 29, No. 3, pp. 391–398), C. Blem and L. Blem examined the reproductive characteristics of the eastern cottonmouth. The data
> Refer to Problem 6. Determine a 90% confidence interval for the difference between the mean right-leg strengths of males and females. Interpret your result. Data from Problem 6: In the paper, “Sex Differences in Static Strength and Fatigability in Three
> In the paper, “Sex Differences in Static Strength and Fatigability in Three Different Muscle Groups” (Reasearch Quarterly for Exercise and Sport, Vol. 61(3), pp. 238–242), J. Misner et al. published results of a study on grip and leg strength of males an
> Explain one possible advantage of using a paired sample instead of independent samples.
> Suppose that the variable under consideration is normally distributed on each of the two populations and that you are going to use independent simple random samples to compare the population means. Fill in the blank and explain your answer: Unless you ar
> Regarding the pooled and nonpooled t-procedures, a. what is the difference in assumptions between the two procedures? b. how important is the assumption of independent simple random samples for these procedures? c. how important is the normality assumpti
> The Bureau of Labor Statistics publishes data on weekly earnings of full-time wage and salary workers in Employment and Earnings. Male and female workers were paired according to occupation and experience. Their weekly earnings, in dollars, are provided
> Discuss the basic strategy for comparing the means of two populations based on a simple random paired sample.
> I. Ertugrul et al. conducted a study to determine the association between insulin growth factor 1 (IGF-1) and bone mineral density (BMD) in men over 65 years of age. The researchers published their results in the paper “Relationship Between Insulin-Like
> In the paper, “Drink and Be Merry? Gender, Life Satisfaction, and Alcohol Consumption Among College Students” (Psychology of Addictive Behaviors, Vol. 19, Issue 2, pp. 184–191), J. Murphy et al. examined the impact of alcohol use and alcohol-related prob
> We have presented some quantitative data sets and specified a grouping method for practicing the concepts. For each data set, a. determine a frequency distribution. b. obtain a relative-frequency distribution. c. construct a frequency histogram based on
> For independent samples, the graphs are for the two samples; for a paired sample, the graphs are for the paired differences. The intent is to employ the sample data to perform a hypothesis test to compare the means of the two populations from which the d
> For independent samples, the graphs are for the two samples; for a paired sample, the graphs are for the paired differences. The intent is to employ the sample data to perform a hypothesis test to compare the means of the two populations from which the d
> For independent samples, the graphs are for the two samples; for a paired sample, the graphs are for the paired differences. The intent is to employ the sample data to perform a hypothesis test to compare the means of the two populations from which the d
> For independent samples, the graphs are for the two samples; for a paired sample, the graphs are for the paired differences. The intent is to employ the sample data to perform a hypothesis test to compare the means of the two populations from which the d
> For independent samples, the graphs are for the two samples; for a paired sample, the graphs are for the paired differences. The intent is to employ the sample data to perform a hypothesis test to compare the means of the two populations from which the d
> Find a 90% confidence interval for the difference in the mean lengths of time that ice stays on the two lakes. Interpret your result.
> In the on-line paper “Changes in Lake Ice: Ecosystem Response to Global Change” (Teaching Issues and Experiments in Ecology, tiee.ecoed.net, Vol. 3), R. Bohanan et al. questioned whether there is evidence for global warming in long-term data on changes i
> Discuss the basic strategy for comparing the means of two populations based on independent simple random samples.
> Suppose that you want to conduct a left-tailed hypothesis test at the 5% significance level. How must the critical value be chosen?
> We have presented some quantitative data sets and specified a grouping method for practicing the concepts. For each data set, a. determine a frequency distribution. b. obtain a relative-frequency distribution. c. construct a frequency histogram based on
> True or false: A critical value is considered part of the rejection region.
> Explain the meaning of each term. a. rejection region b. nonrejection region c. critical value(s)
> For a fixed sample size, what happens to the probability of a Type II error if the significance level is decreased from 0.05 to 0.01?
> Two types of incorrect decisions can be made in a hypothesis test: a Type I error and a Type II error. a. Explain the meaning of each type of error. b. Identify the letter used to represent the probability of each type of error. c. If the null hypothesis
> According to the Beer Institute Annual Report, the mean annual consumption of beer per person in the United States is 28.2 gallons (roughly 300 twelve-ounce bottles). A random sample of 300 Missouri residents yielded the annual beer consumption provided
> Body mass index (BMI) is a measure of body fat based on height and weight. According to Dietary Guidelines for Americans, published by the U.S. Department of Agriculture and the U.S. Department of Health and Human Services, for adults, a BMI of greater t
> There are three possible alternative hypotheses in a hypothesis test for a population mean. Identify them and explain when each is used.
> According to Food Consumption, Prices, and Expenditures, published by the U.S. Department of Agriculture, the mean consumption of beef per person in 2011 was 57.5 lb. A sample of 40 people taken this year yielded the data, in pounds, on last year’s beef
> The normal probability plot and stem-and-leaf diagram of the data are shown in Fig; σ is known.
> The normal probability plot and stem-and-leaf diagram of the data are shown in Fig; σ is known.
> Information provided by the World Meteorological Association revealed the following data on the highest recorded temperature for each continent. a. What type of data is presented in the first column of the table? b. What type of data is presented in the
> The normal probability plot and stem-and-leaf diagram of the data are shown in Fig; σ is unknown.
> The normal probability plot and stem-and-leaf diagram of the data are shown in Fig; σ is unknown.
> The normal probability plot and stem-and-leaf diagram of the data are shown in Fig; σ is unknown.
> The normal probability plot and histogram of the data are shown in Fig; σ is unknown.
> The normal probability plot and histogram of the data are shown in Fig; σ is known.
> The normal probability plot and stem-and-leaf diagram of the data are shown in Fig. σ is known.
> The normal probability plot and stem-and-leaf diagram of the data are depicted in Fig. σ is unknown.
> Regarding a hypothesis test: a. What is the procedure, generally, for deciding whether the null hypothesis should be rejected? b. How can the procedure identified in part (a) be made objective and precise?
> The normal probability plot and histogram of the data are depicted in Fig; σ is known.
> College basketball, and particularly the NCAA basketball tournament, is a popular venue for gambling, from novices in office betting pools to high rollers. To encourage uniform betting across teams, Las Vegas oddsmakers assign a point spread to each game
> We have presented a “data scenario.” In each case, decide which type of grouping (single-value, limit, or cutpoint) is probably the best? The carapace lengths, to the nearest hundredth of a millimeter, of a sample of 50 giant tarantulas.
> The Federal Bureau of Investigation (FBI) compiles information on robbery and property crimes by type and selected characteristic and publishes its findings in Uniform Crime Reports. According to that document, the mean value lost to purse snatching was
> The following table provides last year’s cheese consumption, in pounds, for 35 randomly selected Americans. a. At the 10% significance level, do the data provide sufficient evidence to conclude that last year’s mean cheese consumption for all Americans h
> Cheese Consumption. The null and alternative hypotheses for the hypothesis test are, respectively, H0: μ = 33 lb (mean has not increased) Ha: μ > 33 lb (mean has increased), where μ is last year’s mean cheese consumption for all Americans. Explain what
> The U.S. Department of Agriculture reports in Food Consumption, Prices, and Expenditures that the average American consumed 33 lb of cheese in 2010. Suppose that you want to decide whether last year’s mean cheese consumption is greater than the 2010 mean
> In each part, we have identified a hypothesis-testing procedure for one population mean. State the assumptions required and the test statistic used in each case. a. one-mean t-test b. one-mean z-test
> Discuss the difference between statistical significance and practical significance.
> What is meant when we say that a hypothesis test is a. exact? b. approximately corrects?
> Assess the evidence against the null hypothesis if the P-value of the hypothesis test is 0.062.
> The following statement appeared on a box of Tide laundry detergent: “Individual packages of Tide may weigh slightly more or less than the marked weight due to normal variations incurred with high speed packaging machines, but each day’s production of Ti
> State the general steps of the P-value approach to hypothesis testing.
> We have presented a “data scenario.” In each case, decide which type of grouping (single-value, limit, or cutpoint) is probably the best? The gas mileages, rounded to the nearest number of miles per gallon, of all new car models.
> In each part, we have given the value obtained for the test statistic, z, in a one-mean z-test. We have also specified whether the test is two tailed, left tailed, or right tailed. Determine the P-value in each case and decide whether, at the 5% signific
> How is the P-value of a hypothesis test actually determined?
> Explain why the P-value of a hypothesis test is also referred to as the observed significance level.
> State the decision criterion for a hypothesis test, using the P-value.
> True or false: A P-value of 0.02 provides more evidence against the null hypothesis than a P-value of 0.03. Explain your answer.
> Define the P-value of a hypothesis test.
> State the general steps of the critical-value approach to hypothesis testing.
> The following graph portrays the decision criterion for a one mean z-test, using the critical-value approach to hypothesis testing. The curve in the graph is the normal curve for the test statistic under the assumption that the null hypothesis is true. D
> Determine the critical value(s) for a one-mean z-test at the 1% significance level if the test is a. right tailed. b. left tailed. c. two tailed.
> Explain the meaning of each term. a. null hypothesis b. alternative hypothesis c. test statistic d. significance level
> We have presented a “data scenario.” In each case, decide which type of grouping (single-value, limit, or cutpoint) is probably the best? The number of automobiles per family.
> A variable of a population has a mean of 266 and a standard deviation of 16. Ten observations of this variable have a mean of 262.1 and a sample standard deviation of 20.4. Obtain the observed value of the a. standardized version of x¯. b. studentized v
> Suppose that you plan to apply the one-mean z-interval procedure to obtain a 90% confidence interval for a population mean, μ. You know that σ = 12 and that you are going to use a sample of size 9. a. What will be your margin of error? b. What else do yo