Concept explainers
Exercises 5–8 refer to the study of an association between which ear is used for cell phone calls and whether the subject is left-handed or right-handed. The study is reported in “Hemispheric Dominance and Cell Phone Use,” by Seidman et al., JAMA Otolaryngology—Head & Neck Surgery, Vol. 139, No. 5. The study began with a survey e-mailed to 5000people belonging to an otology online group, and 717 surveys were returned. (Otology relates to the ear and hearing.)
5. Sampling Method What type of sampling best describes the way in which the 717 subjects were chosen: simple random sample, systematic sample, convenience sample, stratified sample, cluster sample? Does the method of sampling appear to adversely affect the quality of the results?
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MA 180 MYMATHLAB ACCESS
- A paper investigated the driving behavior of teenagers by observing their vehicles as they left a high school parking lot and then again at a site approximately 1 2 mile from the school. Assume that it is reasonable to regard the teen drivers in this study as representative of the population of teen drivers. MaleDriver FemaleDriver 1.3 -0.3 1.3 0.6 0.9 1.1 2.1 0.7 0.7 1.1 1.3 1.2 3 0.1 1.3 0.9 0.6 0.5 2.1 0.5 (a) Use a .01 level of significance for any hypothesis tests. Data consistent with summary quantities appearing in the paper are given in the table. The measurements represent the difference between the observed vehicle speed and the posted speed limit (in miles per hour) for a sample of male teenage drivers and a sample of female teenage drivers. (Use ?males − ?females. Round your test statistic to two decimal places. Round your degrees of freedom down to the nearest whole number. Round your p-value to three decimal places.) t = df =…arrow_forwardA paper investigated the driving behavior of teenagers by observing their vehicles as they left a high school parking lot and then again at a site approximately 1 2 mile from the school. Assume that it is reasonable to regard the teen drivers in this study as representative of the population of teen drivers. MaleDriver FemaleDriver 1.4 -0.2 1.2 0.5 0.9 1.1 2.1 0.7 0.7 1.1 1.3 1.2 3 0.1 1.3 0.9 0.6 0.5 2.1 0.5 (a) Use a .01 level of significance for any hypothesis tests. Data consistent with summary quantities appearing in the paper are given in the table. The measurements represent the difference between the observed vehicle speed and the posted speed limit (in miles per hour) for a sample of male teenage drivers and a sample of female teenage drivers. (Use ?males − ?females. Round your test statistic to two decimal places. Round your degrees of freedom down to the nearest whole number. Round your p-value to three decimal places.) t = df =…arrow_forwardIn the book Business Research Methods (5th ed.), Donald R. Cooper and C. William Emory discuss studying the relationship between on-the-job accidents and smoking. Cooper and Emory describe the study as follows: Suppose a manager implementing a smoke-free workplace policy is interested in whether smoking affects worker accidents. Since the company has complete reports of on-the-job accidents, she draws a sample of names of workers who were involved in accidents during the last year. A similar sample from among workers who had no reported accidents in the last year is drawn. She interviews members of both groups to determine if they are smokers or not. The sample results are given in the following table. On-the-Job Accident Smoker Yes No Row Total Heavy 12 5 17 Moderate 9 10 19 Nonsmoker 13 17 30 Column total 34 32 66 Expected counts are below observed counts Accident No Accident Total Heavy 12 5 17 8.76 8.24…arrow_forward
- 6. In the book Business Research Methods (5th ed.), Donald R. Cooper and C. William Emory discuss studying the relationship between on-the-job accidents and smoking. Cooper and Emory describe the study as follows: Suppose a manager implementing a smoke-free workplace policy is interested in whether smoking affects worker accidents. Since the company has complete reports of on-the-job accidents, she draws a sample of names of workers who were involved in accidents during the last year. A similar sample from among workers who had no reported accidents in the last year is drawn. She interviews members of both groups to determine if they are smokers or not. The sample results are given in the following table.arrow_forwardAn automotive engineer is investigating two different types of metering devices for an electronic fuel injection system to determine whether they differ in their fuel mileage performance. The system is installed on 10 different cars, and a test is run with each metering device on each car. The data is provided below: Metering Device Car 1 2 1 17.6 16.8 2 19.4 20.0 3 18.2 17.6 4 17.1 16.4 5 15.3 16.0 6 15.9 15.9 7 16.3 16.5 8 18.0 18.4 9 17.3 16.4 10 19.1 20.1 Is there a significant difference between the means of the two metering devices? Use . Interpret the result in the context of the problem. An article in the journal Hazardous Waste and Hazardous Materials (Vol. 6, 1989) reported the results of an analysis of the weight of calcium in standard cement and cement doped with lead. Reduced levels of calcium would indicate that the hydration mechanism in the cement is blocked…arrow_forwardIn a study, 10 healthy men were exposed to diesel exhaust for 1 hour. A measure of brain activity (called median power frequency, or MPF in Hz) was recorded at two different locations in the brain both before and after the diesel exhaust exposure. The resulting data are given in the accompanying table. For purposes of this exercise, assume that the sample of 10 men is representative of healthy adult males. Subject MPF (in Hz) Location 1before Location 1after Location 2before Location 2after 1 6.4 8.0 6.9 9.4 2 8.6 12.7 9.5 11.2 3 7.4 8.4 6.6 10.2 4 8.6 9.0 9.0 9.7 5 9.8 8.4 9.6 9.2 6 8.9 11.0 9.0 11.9 7 9.1 14.4 7.9 9.3 8 7.4 11.1 8.1 9.1 9 6.7 7.3 7.2 8.0 10 8.9 11.2 7.4 9.3 Construct a 90% confidence interval estimate for the difference in mean MPF at brain location 1 (in Hz) before and after exposure to diesel exhaust. (Hint: See Example 13.7.) (Use ?d = ?before − ?after. Use a table or technology. Round your answers to two decimal places.)…arrow_forward
- A panel of dentists is interested in testing two different toothpaste brands (A and B) to see if there is a relationship between the brand and whether or not the patient has a cavity at their next appointment. A representative sample of 60 patients is recruited to take part in this study. At their first appointment of the year, each subject is assigned to brush their teeth with one of the two brands for the next six months. At their follow-up appointment six months later, they were checked for cavities. ******In the sample, 6 of the 30 patients assigned to Brand A were found to have a cavity. The fraction 6/30 should be denoted by which of the following? μ x̄ p p̂ n s σ χ²arrow_forwardA panel of dentists is interested in testing two different toothpaste brands (A and B) to see if there is a relationship between the brand and whether or not the patient has a cavity at their next appointment. A representative sample of 60 patients is recruited to take part in the study. At their first appointment of the year, each subject is assigned to brush their teeth with one of the two brands for the next six months. At their follow-up appointment six months later, they were checked for cavities. What method of data collection was used? Select one: a.Experiment b.Observational Studyarrow_forwardA panel of dentists is interested in testing two different toothpaste brands (A and B) to see if there is a relationship between the brand and whether or not the patient has a cavity at their next appointment. A representative sample of 60 patients is recruited to take part in the study. At their first appointment of the year, each subject is assigned to brush their teeth with one of the two brands for the next six months. At their follow-up appointment six months later, they were checked for cavities. To test for significance of their findings, which of the following should the dentists use? Select one: a.Paired t-test b.One-sample t-test for a mean c.Linear Regression d.One-sample Z-test for a proportion e.Chi-Square test for independence f.Two-Sample t-test g.One-sample Z-test for a meanarrow_forward
- A sample of 26 offshore oil workers took part in a simulated escape exercise, resulting in the accompanying data on time (sec) to complete the escape (“Oxygen Consumption and Ventilation During Escape from an Offshore Platform,” Ergonomics, 1997: 281-292): 389 356 359 363 375 424 325 394 402 373 373 370 364 366 364 325 339 393 392 369 374 359 356 403 334 397 a. Construct a stem-and-leaf display of the data. How does it suggest that the sample mean and median will compare?b. Calculate the values of the sample mean and median. [Hint: Σxi = 9638.]c. By how much could the largest time, currently 424, be increased without affecting the value of the sample median? By how much could this value be decreased without affecting the value of the sample median?d. What are the values of x and x when the observations are reexpressed in minutes?arrow_forwardThe article “Effects of Diets with Whole Plant-Origin Proteins Added with Different Ratiosof Taurine:Methionine on the Growth, Macrophage Activity and Antioxidant Capacity ofRainbow Trout (Oncorhynchus mykiss) Fingerlings” (O. Hernandez, L. Hernandez, et al.,Veterinary and Animal Science, 2017:4-9) reports that a sample of 210 juvenile rainbowtrout fed a diet fortified with equal amounts of the amino acids taurine and methionine for aperiod of 70 days had a mean weight gain of 313 percent with a standard deviation of 25, while 210 fish fed with a control diet had a mean weight gain of 233 percent with a standard deviation of 19. Units are percent. Find a 99% confidence interval for the difference in weight gain on the two diets.arrow_forwardIn a study of a group of women science majors who remained in their profession and a group who left their profession within a few months of graduation, the researchers collected the data shown here on a self-esteem questionnaire. Leavers Stayers1 = 3.05 2 = 2.92σ1 = 0.71 σ2 = 0.71n1 = 100 n2 = 227At α = 0.05, can it be concluded that there is a difference in the self-esteem scores of the two groups? Use the P-value method.arrow_forward
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