[SOLVED] Determine a 98% confidence interval for the

> Use the two-proportions plus four z-interval procedure to find the required confidence interval. Interpret your results. Since 1973, Gallup has asked Americans how much confidence they have in a variety of U.S. institutions. One question asked of those p

> x1 = 30, n1 = 80, x2 = 15, n2 = 20; 95% confidence interval a. use the two-proportions plus-four z-interval procedure to find the required confidence interval for the difference between the two population proportions. b. compare your result with the corr

> x1 = 18, n1 = 30, x2 = 10, n2 = 20; 95% confidence interval a. use the two-proportions plus-four z-interval procedure to find the required confidence interval for the difference between the two population proportions. b. compare your result with the corr

> x1 = 15, n1 = 20, x2 = 18, n2 = 30; 90% confidence interval a. use the two-proportions plus-four z-interval procedure to find the required confidence interval for the difference between the two population proportions. b. compare your result with the corr

> x1 = 14, n1 = 20, x2 = 8, n2 = 20; 90% confidence interval a. use the two-proportions plus-four z-interval procedure to find the required confidence interval for the difference between the two population proportions. b. compare your result with the corre

> As reported by the U.S. Census Bureau in Educational Attainment in the United States, the percentage of adults in each state and the District of Columbia who have completed high school is provided on the WeissStats site. a. use the technology of your cho

> x1 = 18, n1 = 40, x2 = 30, n2 = 40; 80% confidence interval a. use the two-proportions plus-four z-interval procedure to find the required confidence interval for the difference between the two population proportions. b. compare your result with the corr

> x1 = 10, n1 = 20, x2 = 18, n2 = 30; 80% confidence interval a. use the two-proportions plus-four z-interval procedure to find the required confidence interval for the difference between the two population proportions. b. compare your result with the corr

> In the New York Times article “College Graduates Fare Well in Jobs Market, Even through Recession,” C. Rampell noted that college graduates have suffered through the recession and lackluster recovery with remarkable resilience. Of a random sample of 1020

> Neutropenia is an abnormally low number of neutrophils (a type of white blood cell) in the blood. Chemotherapy often reduces the number of neutrophils to a level that makes patients susceptible to fever and infections. G. Bucaneve et al. published a stud

> Repeat parts (b)–(e) of Exercise 11.9 for samples of size 4. Data from Exercise 11.9: This exercise involves the use of an unrealistically small population to provide a concrete illustration for the exact distribution of a sample proportion. A populatio

> The Organization for Economic Cooperation and Development (OECD) summarizes data on labor-force participation rates in OECD in Figures. Independent simple random samples were taken of 300 U.S. women and 250 Canadian women. Of the U.S. women, 215 were fou

> An issue of Science News (Vol. 163, No. 22, pp. 341–342) reported that the Women’s Health Initiative cast doubts on the benefit of hormone-replacement therapy. Researchers randomly divided 4532 healthy women over the age of 65 years into two groups. One

> Apply Procedure to find the required confidence interval. Refer to Exercise 11.111 and find and interpret a 90% confidence interval for the difference between the percentages of adults in the two degree categories who have an above healthy weight. Data

> Apply Procedure to find the required confidence interval. Refer to Exercise 11.110 and find and interpret a 98% confidence interval for the difference between the percentages of women and men who favor ballistic fingerprinting. Data from Exercise 11.110

> Apply Procedure to find the required confidence interval. Refer to Exercise 11.109 and find and interpret a 99% confidence interval for the difference between the proportions of seat-belt users for drivers in the age groups 16–24 years and 25–69 years.

> In the article, “Length of The Beatles’ Songs” (Chance, Vol. 25, No. 1, pp. 30–33), T. Koyama discusses aspects and interpretations of the lengths of songs by The Beatles. Data on the length, in seconds, of 229 Beatles’ songs are presented on the WeissSt

> Apply Procedure to find the required confidence interval. Refer to Exercise 11.108 and find and interpret a 95% confidence interval for the difference between the stroke incidences of white and African-American elderly. Data from Exercise 11.108: In the

> Apply Procedure to find the required confidence interval. Refer to Exercise 11.107 and determine and interpret a 98% confidence interval for the difference between the rates of major birth defects for babies born to women who have taken folic acid and th

> Apply Procedure to find the required confidence interval. Refer to Exercise 11.106 and determine and interpret a 98% confidence interval for the difference between the prostate cancer rates of men who have had a vasectomy and those who have not. Data fr

> Body mass index (BMI) is a measure of body fat based on height and weight. According to the document 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

> Guns make unique markings on bullets they fire and their shell casings. These markings are called ballistic fingerprints. An ABCNEWS Poll examined the opinions of Americans on the enactment of a law “. . .that would require every gun sold in the United S

> Repeat parts (b)–(e) of Exercise 11.9 for samples of size 3. Data from Exercise 11.9: This exercise involves the use of an unrealistically small population to provide a concrete illustration for the exact distribution of a sample proportion. A populatio

> The National Highway Traffic Safety Administration collects data on seat-belt use and publishes results in the document Occupant Restraint Use. Of 1000 drivers 16–24 years old, 79% said that they buckle up, whereas 924 of 1100 drivers 25–69 years old sai

> In the paper “The Racial Crossover in Comorbidity, Disability, and Mortality” (Demography, Vol. 37(3), pp. 267–283), N. Johnson investigated the health of independent random samples of white and African-American elderly (aged 70 years or older). Of the 4

> For several years, evidence had been mounting that folic acid reduces major birth defects. A. Czeizel and I. Dudas of the National Institute of Hygiene in Budapest directed a study that provided the strongest evidence to date. Their results were publishe

> In the United States, approximately 450,000 vasectomies are performed each year. In this surgical procedure for contraception, the tube carrying sperm from the testicles is cut and tied. Several studies have been conducted to analyze the relationship bet

> In an article titled “Great White, Deep Trouble” (National Geographic, Vol. 197(4), pp. 2–29), Peter Benchley—the author of JAWS—discussed various aspects of the Great White Shark (Carcharodon carcharias). Data on the number of pups borne in a lifetime b

> In the 1940s and early 1950s, the public was greatly concerned about polio. In an attempt to prevent this disease, Jonas Salk of the University of Pittsburgh developed a polio vaccine. In a test of the vaccine’s efficacy, involving nearly 2 million grade

> x1 = 30, n1 = 80, x2 = 15, n2 = 20; two-tailed test, α = 0.05; 95% confidence interval We have provided the numbers of successes and the sample sizes for independent simple random samples from two populations. a. Determine the sample proportions. b. Deci

> x1 = 18, n1 = 30, x2 = 10, n2 = 20; two-tailed test, α = 0.05; 95% confidence interval We have provided the numbers of successes and the sample sizes for independent simple random samples from two populations. a. Determine the sample proportions. b. Deci

> x1 = 15, n1 = 20, x2 = 18, n2 = 30; right-tailed test, α = 0.05; 90% confidence interval We have provided the numbers of successes and the sample sizes for independent simple random samples from two populations. a. Determine the sample proportions. b. De

> x1 = 14, n1 = 20, x2 = 8, n2 = 20; right-tailed test, α = 0.05; 90% confidence interval We have provided the numbers of successes and the sample sizes for independent simple random samples from two populations. a. Determine the sample proportions. b. Dec

> x1 = 18, n1 = 40, x2 = 30, n2 = 40; left-tailed test, α = 0.10; 80% confidence interval We have provided the numbers of successes and the sample sizes for independent simple random samples from two populations. a. Determine the sample proportions. b. Dec

> x1 = 10, n1 = 20, x2 = 18, n2 = 30; left-tailed test, α = 0.10; 80% confidence interval We have provided the numbers of successes and the sample sizes for independent simple random samples from two populations. a. Determine the sample proportions. b. Dec

> Repeat parts (b)–(e) of Exercise 11.9 for samples of size 1. Data from Exercise 11.9: This exercise involves the use of an unrealistically small population to provide a concrete illustration for the exact distribution of a sample proportion. A populatio

> An independent golf equipment testing facility compared the difference in the performance of golf balls hit off a regular 2-3/4’’ wooden tee to those hit off a 3’’ Stinger Competition golf tee. A Callaway Great Big Bertha driver with 10 degrees of loft w

> L. Petersen et al. evaluated the effects of integrated treatment for patients with a first episode of psychotic illness in the paper “A Randomised Multicentre Trial of Integrated Versus Standard Treatment for Patients with a First Episode of Psychotic Il

> We conducted a non-pooled t-test, at the 5% significance level, to decide whether the mean operative time is less with the dynamic system than with the static system. Use the technology of your choice to perform the following tasks. a. Using a pooled t-t

> In the article “Trophic Interaction Cycles in Tundra Ecosystems and the Impact of Climate Change”, R. Ims and E. Fuglei provided an overview of animal species in the northern tundra. One threat to the snow goose in arctic Canada is the lemming. Snowy owl

> You conducted a non-pooled t-test to decide whether the mean number of acute postoperative days spent in the hospital is smaller with the dynamic system than with the static system. Use the technology of your choice to perform the following tasks. a. Usi

> A mutual fund is a professionally managed investment that can be sold to the general public. Mutual funds can be specialized into different categories such as healthcare-related or technology-related mutual funds. The following table lists the 3-month ra

> L. Grossback et al. examined mandate perceptions and their causes in the paper “Comparing Competing Theories on the Causes of Mandate Perceptions” (American Journal of Political Science, Vol. 49, Issue 2, pp. 406–419). The following are data on the perce

> In the article “Sleep Apnea in Adults With Traumatic Brain Injury: A Preliminary Investigation” (Archives of Physical Medicine and Rehabilitation, Vol. 82, Issue 3, pp. 316– 321), J. Webster et al. investigated sleep-related breathing disorders in adults

> Refer to Exercise 10.86 and find a 99% confidence interval for the difference between the mean wing lengths of the two subspecies. Data from Exercise 10.86: D. Cristol et al. published results of their studies of two subspecies of dark-eyed juncos in th

> Refer to Exercise 10.85 and determine a 98% confidence interval for the difference between the mean dopamine activities of psychotic and nonpsychotic patients. Data from Exercise 10.85: Previous research has suggested that changes in the activity of dop

> Refer to Exercise 10.84 and find a 90% confidence interval for the difference between the mean heart rates of urban bus drivers in Stockholm in the two environments. Data from Exercise 10.84: An intervention program designed by the Stockholm Transit Dis

> The primary concern is deciding whether the mean of Population 1 is less than the mean of Population 2. a. Determine the null and alternative hypotheses. b. Classify the hypothesis test as two tailed, left tailed, or right tailed.

> Refer to Exercise 10.83 and find a 90% confidence interval for the difference between the mean numbers of acute postoperative days in the hospital with the dynamic and static systems. Data from Exercise 10.83: The researchers also obtained the following

> Old Faithful is a geyser in Yellowstone National Park that erupts at relatively predictable intervals. Since 2000, the eruptions of Old Faithfull occur on average every 90 minutes. Information on the daily eruptions of Old Faithful can be found on the we

> Obtain a 90% confidence interval for the difference, μ1 − μ2, between the mean ages at arrest of East German prisoners with chronic PTSD and remitted PTSD.

> D. Cristol et al. published results of their studies of two subspecies of dark-eyed juncos in the article “Migratory Dark-Eyed Juncos, Junco Hyemalis, Have Better Spatial Memory and Denser Hippocampal Neurons than Nonmigratory Conspecifics” (Animal Behav

> Previous research has suggested that changes in the activity of dopamine, a neurotransmitter in the brain, may be a causative factor for schizophrenia. In the paper “Schizophrenia: Dopamine β-Hydroxylase Activity and Treatment Response” (Science, Vol. 21

> An intervention program designed by the Stockholm Transit District was implemented to improve the work conditions of the city’s bus drivers. Improvements were evaluated by G. Evans et al., who collected physiological and psychological data for bus driver

> The researchers also obtained the following data on the number of acute postoperative days in the hospital using the dynamic and static systems. At the 5% significance level, does the data provide sufficient evidence to conclude that the mean number of a

> Phyllodes tumors of the breast are rare tumors that represent less than one percent of growths in the breast. Researchers I. Youn et al. presented characteristics of phyllodes tumors in the article “Phyllodes Tumors of the Breast: Ultrasonographic Findin

> According to the American Psychiatric Association, posttraumatic stress disorder (PTSD) is a common psychological consequence of traumatic events that involve a threat to life or physical integrity. During the Cold War, some 200,000 people in East German

> We have provided summary statistics for independent simple random samples from two populations. In each case, use the non-pooled t-test and the non-pooled t-interval procedure to conduct the required hypothesis test and obtain the specified confidence in

> The primary concern is deciding whether the mean of Population 2 is greater than the mean of Population 1. a. Determine the null and alternative hypotheses. b. Classify the hypothesis test as two tailed, left tailed, or right tailed.

> We have provided summary statistics for independent simple random samples from two populations. In each case, use the non-pooled t-test and the non-pooled t-interval procedure to conduct the required hypothesis test and obtain the specified confidence in

> The Bureau of Economic Analysis gathers information on the length of stay in Europe and the Mediterranean by U.S. travelers. Data are published in Survey of Current Business. The following stem-and-leaf diagram portrays the length of stay, in days, of a

> We have provided summary statistics for independent simple random samples from two populations. In each case, use the non-pooled t-test and the non-pooled t-interval procedure to conduct the required hypothesis test and obtain the specified confidence in

> Discuss the relative advantages and disadvantages of using pooled and non-pooled t-procedures.

> Each pair of graphs in Fig. 10.8 shows the distributions of a variable on two populations. Suppose that, in each case, you want to perform a small-sample hypothesis test based on independent simple random samples to compare the means of the two populatio

> suppose that you know that a variable is normally distributed on each of two populations. Further suppose that you want to perform a hypothesis test based on independent random samples to compare the two population means. Decide whether you would use the

> The primary concern is deciding whether the mean of Population 1 is greater than the mean of Population 2. a. Determine the null and alternative hypotheses. b. Classify the hypothesis test as two tailed, left tailed, or right tailed.

> A study published by E. Anionwu et al. in the British Medical Journal (Vol. 282, pp. 283–286) measured the steady-state hemoglobin levels of patients with three different types of sickle cell disease. Following is a stem-and-leaf diagram of the data.

> suppose that you know that a variable is normally distributed on each of two populations. Further suppose that you want to perform a hypothesis test based on independent random samples to compare the two population means. Decide whether you would use the

> Suppose that you want to perform a hypothesis test to compare the means of two populations, using independent simple random samples. Assume that the two distributions of the variable under consideration have the same shape, but are not normal, and both s

> Suppose that you want to perform a hypothesis test to compare the means of two populations, using independent simple random samples. Assume that the two distributions (one for each population) of the variable under consideration are normally distributed

> If the assumptions for a pooled t-interval are satisfied, the formula for a (1 − α)-level lower confidence bound for the difference, μ1 − μ2, between two population means is For a right-tailed hypothesis test at the significance level α, the null hypothe

> If the assumptions for a pooled t-interval are satisfied, the formula for a (1 − α)-level upper confidence bound for the difference, μ1 − μ2, between two population means is For a left-tailed hypothesis test at the significance level α, the null hypothes

> As we mentioned, the following relationship holds between hypothesis tests and confidence intervals: For a two-tailed hypothesis test at the significance level α, the null hypothesis H0: μ1 = μ2 will be rejected in favor of the alternative hypothesis Ha:

> In this exercise, you are to perform a computer simulation to illustrate the distribution of the pooled t-statistic, given in Key Fact. a. Simulate 1000 random samples of size 4 from a normally distributed variable with a mean of 100 and a standard devia

> The formula for the pooled variance, s2p. Show that, if the sample sizes, n1 and n2, are equal, then s2p is the mean of s21 and s22.

> In this section, we introduced the pooled t-test, which provides a method for comparing two population means. In deriving the pooled t-test, we stated that the variable cannot be used as a basis for the required test statistic because σ is unknown. Why c

> The primary concern is deciding whether the mean of Population 2 is less than the mean of Population 1. a. Determine the null and alternative hypotheses. b. Classify the hypothesis test as two tailed, left tailed, or right tailed.

> According to the National Health and Nutrition Examination Survey, published by the Centers for Disease Control and Prevention, the average cholesterol level for children between 4 and 19 years of age is 165 mg/dL. A pediatrician who tested the cholester

> An independent golf equipment testing facility compared the difference in the performance of golf balls hit off a regular 2-3/4’’ wooden tee to those hit off a 3’’ Stinger Competition golf tee. A Callaway Great Big Bertha driver with 10 degrees of loft w

> The paper “Correlations Between the Intrauterine Metabolic Environment and Blood Pressure in Adolescent Offspring of Diabetic Mothers” (Journal of Pediatrics, Vol. 136, Issue 5, pp. 587–592) by N. Cho et al. presented findings of research on children of

> Philosophical and health issues are prompting an increasing number of Taiwanese to switch to a vegetarian lifestyle. In the paper “LDL of Taiwanese Vegetarians Are Less Oxidizable than Those of Omnivores” (Journal of Nutrition, Vol. 130, pp. 1591–1596),

> Refer to Exercise 10.50 and find a 98% confidence interval for the difference between the mean amount of food wasted for lunches before recess and that for lunches after recess. Data from Exercise 10.50: E. Bergman et al. conducted a study to determine,

> Refer to Exercise 10.49 and determine a 99% confidence interval for the difference between mean spleen lengths of Nigerian males and females. Data from Exercise 10.49: O. Ehimwenma and M. Tagbo, researchers in Nigeria, were interested in how characteris

> Refer to Exercise 10.48 and determine a 95% confidence interval for the difference between last year’s mean VMTs by midwestern and southern households. Data from Exercise 10.48: Data on household vehicle miles of travel (VMT) are compiled annually by th

> Refer to Exercise 10.47 and find a 90% confidence interval for the difference between the mean reductions in PTH levels for fortified and unfortified orange juice. Data from Exercise 10.47: V. Tangpricha et al. did a study to determine whether fortifyin

> Refer to Exercise 10.46 and obtain a 98% confidence interval for the difference between the mean absolute pointing errors for males and females. Data from Exercise 10.46: In the paper “The Relation of Sex and Sense of Direction to Spatial Orientation in

> Refer to Exercise 10.45 and obtain a 90% confidence interval for the difference between the mean times served by prisoners in the fraud and firearms offense categories. Data from Exercise 10.45: The Federal Bureau of Prisons publishes data in Prison Sta

> E. Bergman et al. conducted a study to determine, among other things, the impact that scheduling recess before or after the lunch period has on wasted food for students in grades three through five. Results were published in the online article “The Relat

> The Internal Revenue Service (IRS) publishes data on adjusted gross incomes in the document Statistics of Income, Individual Income Tax Returns. The following relative-frequency histogram shows one year’s individual income tax returns for adjusted gross

> The primary concern is deciding whether the mean of Population 1 differs from the mean of Population 2. a. Determine the null and alternative hypotheses. b. Classify the hypothesis test as two tailed, left tailed, or right tailed.

> O. Ehimwenma and M. Tagbo, researchers in Nigeria, were interested in how characteristics of the spleen of residents in their tropical environment compare to those found elsewhere in the world. They published their findings in the article “Determination

> Data on household vehicle miles of travel (VMT) are compiled annually by the Federal Highway Administration and are published in National Household Travel Survey, Summary of Travel Trends. Independent random samples of 15 midwestern households and 14 sou

> V. Tangpricha et al. did a study to determine whether fortifying orange juice with Vitamin D would result in changes in the blood levels of five biochemical variables. One of those variables was the concentration of parathyroid hormone (PTH), measured in

> In the paper “The Relation of Sex and Sense of Direction to Spatial Orientation in an Unfamiliar Environment” (Journal of Environmental Psychology, Vol. 20, pp. 17–28), J. Sholl et al. published the results of examining the sense of direction of 30 male

> The Federal Bureau of Prisons publishes data in Prison Statistics on the times served by prisoners released from federal institutions for the first time. Independent random samples of released prisoners in the fraud and firearms offense categories yielde

Question: Determine a 98% confidence interval for the