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An electronic implant that stimulates the auditory nerve has been used to restore partial hearing to a number of deaf people. In a study of implant acceptability (Los Angeles Times, January 29, 1985). 250 adults born deaf and 250 adults who went deaf after learning to speak were followed for a period of time after receiving an implant. Of those deaf from birth, 75 had removed the implant, whereas only 25 of those who went deaf after learning to speak had done so. Does this suggest that the true proportion who remove the implants differs for those who were born deaf and those who went deaf after learning to speak? Test the relevant hypotheses using a .01 significance level.Samples of both surface soil and subsoil were taken from eight randomly selected agricultural locations in a particular county. The soil samples were analyzed to determine both surface pH and subsoil p, with the results shown in the accompanying table. 5 7 A Surface pll 6.55 598 5.59 617 592 618 643 5.68 Subsoil pH 6.78 6.14 a. Compute a 90% confidence interval for the mean difference between surface and subsoil pH for agricultural land in this county. b. What assumptions are necessary for the interval in Part (a) to be valid?\fThe color vision of birds plays a role in their foraging behavior: Birds use color to select and avoid certain types of food. The authors of the article "Colour Avoidance in Northern Bobwhites: Effects of Age, Sex, and Previous Experience" (Animal Behaviour (1905]: 519-526) studied the pecking behavior of 1-day-old bobwhites. In an area painted white, they inserted four pins with different colored heads. The color of the pin chosen on the bird's first peck was noted for each of 33 bobwhites, resulting in the accompanying table. Color First Peck Frequency 16 Yellow Red Do the data provide evidence of a color preference? Test using 0= .01.In November 2005, an international study to assess public opinion on the treatment of suspected terrorists was conducted ("Most in U.S., Britain, S. Korea and France Say Torture Is OK in at Least Rare Instances," Associated Press. December 7. 2005). Each individual in random samples of 1000 adults from each of nine different countries was asked the following question: "Do you feel the use of torture against suspected terrorists to obtain information about terrorism activities is justified?" Responses consistent with percentages given in the article for the samples from Italy, Spain, France, the United States, and South Korea are summarized in the table at the top of the next page. Based on these data, is it reasonable to conclude that the response proportions are not the same for all five countries? Use a .01 significance level to test the appropriate hypotheses. Response Some Country Never Barely dmes Often Sure Italy 140 140 30 Spain 5-10 140 70 90 France 400 250 200 120 United 230 270 110 South 40 KoreaAccording to Census Bureau data, in 1998 the California population consisted of 50.7% whites. 8.6% blacks, 30.6% Hispanics, 10.8% Asians, and 1.3%% other ethnic groups. Suppose that a random sample of 1000 students graduating from California colleges and universities in 1998 resulted in the accompanying data on ethnic group. These data are consistent with summary Statistics contained in the article titled "Crumbling Public School System a Threat to California's Future (Investor's Business Daily. November 12. 1999). Fthink Group Number in Sample White 679 51 Hispanic Adan 190 Other 3 Do the data provide evidence that the proportion of students graduating from colleges and universities in California for these ethnic group categories differs from the respective proportions in the population for California? Test the appropriate hypotheses using 0= .01.Criminologists have long debated whether there is a relationship between weather and violent crime. The author of the article "Is There a Season for Homicide?" (Criminology [1989]: 287-298) classified 1361 homicides according to season, resulting in the accompanying data. Do these data support the theory that the homicide rate is not the same over the four seasons? Test the relevant hypotheses using a significance level of .05. Winter Spring Summer Fall 354 372 327Jail inmates can be classified into one of the following four categories according to the type of crime committed: violent crime, crime against property, drug offenses, and public-order offenses. Suppose that random samples of 500 male inmates and 500 female inmates are selected, and each inmate is classified according to type of offense. The data in the accompanying table are based on summary values given in the article "Profile of Jail Inmates" (USA Today. April 25. 1901). We would like to know whether male and female inmates differ with respect to type of offense. Gunder Type of Crime lemak Vink-ne 117 Property 150 Drug 107 Public Order 124 a. Is this a test of homogeneity or a test of independence? b. Test the relevant hypotheses using a significance level of .05
