At Community Hospital, the burn center is experimenting with a new plasma compress treatment. A random sample of n1 = 334 patients with minor burns received the plasma compress treatment. Of these patients, it was found that 266 had no visible scars after treatment. Another random sample of n2 = 418 patients with minor burns received no plasma compress treatment. For this group, it was found that 105 had no visible scars after treatment. Let p1 be the population proportion of all patients with minor burns receiving the plasma compress treatment who have no visible scars. Let p2 be the population proportion of all patients with minor burns not receiving the plasma compress treatment who have no visible scars.   (a) Find a 90% confidence interval for p1 − p2. (Round your answers to three decimal places.) lower limit       upper limit

A random sample of n1 = 157 people ages 16 to 19 were taken from the island of Oahu, Hawaii, and 12 were found to be high school dropouts. Another random sample of n2 = 129 people ages 16 to 19 were taken from Sweetwater County, Wyoming, and 6 were found to be high school dropouts. Do these data indicate that the population proportion of high school dropouts on Oahu is different (either way) from that of Sweetwater County? Use a 1% level of significance. (a) What is the level of significance?   What is the value of the sample test statistic? (Test the difference p1 − p2. Do not use rounded values. Round your final answer to two decimal places.) (c) Find (or estimate) the P-value. (Round your answer to four decimal places.)

A random sample of n1 = 148 people ages 16 to 19 were taken from the island of Oahu, Hawaii, and 14 were found to be high school dropouts. Another random sample of n2 = 125 people ages 16 to 19 were taken from Sweetwater County, Wyoming, and 5 were found to be high school dropouts. Do these data indicate that the population proportion of high school dropouts on Oahu is different (either way) from that of Sweetwater County? Use a 1% level of significance. I need help with sketching, (d) and (e)

According to Pew Research Center surveys, 79% of U.S. adults were using the Internet in January 2011 and 83% were using it in January 2012 (USA TODAY, January 26, 2012). Suppose that these percentages are based on random samples of 1720 U.S. adults in January 2011 and 1970 in January 2012. a. Let p, and p, be the proportions of all U.S. adults who were using the Internet in January 2011 and January 2012, respectively. Construct a 95% confidence interval for p, - P2- Round your answers to three decimal places. to i

The records of a light bulb manufacturer show that, when the manufacturing machinery is working correctly, the defect rate (due to imperfections in the material used) is 1%. The manufacturer's control department periodically tests samples of the bulbs, and when 1.25% or more are defective, they call repair technicians for service. The control department is going to take a random sample of 4400 light bulbs. Let p be the proportion of defective light bulbs in the sample assuming the machinery is working correctly. A) find the mean of p b)find the standard deviation of p c)Compute an approximation for P≥p0.0125, which is the probability that, assuming the machinery is working correctly, the repair technicians will be called. Round your answer to four decimal places.

The records of a light bulb manufacturer show that, when the manufacturing machinery is working correctly, the defect rate (due to imperfections in the material used) is 1%. The manufacturer's control department periodically tests samples of the bulbs, and when 1.25% or more are defective, they call repair technicians for service.   The control department is going to take a random sample of 4400 light bulbs. Let p be the proportion of defective light bulbs in the sample assuming the machinery is working correctly. Answer the following. (If necessary, consult a list of formulas.) (a) Find the mean of p.   (b) Find the standard deviation of p.   (c) Compute an approximation for P(P ≥ 0.0125), which is the probability that, assuming the machinery is working correctly, the repair technicians will be called. Round your answer to four decimal places.

A random sample of n1 = 10 regions in New England gave the following violent crime rates (per million population). x1:   New England Crime Rate 3.8 3.9 5.0 3.4 3.3 4.1 1.8 4.8 2.9 3.1 Another random sample of n2 = 12 regions in the Rocky Mountain states gave the following violent crime rates (per million population). x2:   Rocky Mountain Crime Rate 3.5 4.2 4.6 5.0 3.3 4.8 3.5 2.4 3.1 3.5 5.2 2.8 Assume that the crime rate distribution is approximately normal in both regions. Note: If a two-sample t-test is appropriate, for degrees of freedom d.f. not in the Student's t table, use the closest d.f. that is smaller. In some situations, this choice of d.f. may increase the P-value by a small amount and therefore produce a slightly more "conservative" answer.Use a calculator to calculate  x1 , s1,  x2 , and s2. (Round your answers to two decimal places.) x1 =   s1 =   x2 =   s2 =     (a) Do the data indicate that the violent crime rate in the Rocky Mountain…

The home run percentage is the number of home runs per 100 times at bat. A random sample of 43 professional baseball players gave the following data for home run percentages.

Some commercial airplanes recirculate approximately 50% of the cabin air in order to increase fuel efficiency. The researchers studied 1100 airline passengers, among which some traveled on airplanes that recirculated air and others traveled on planes that did not recirculate air. Of the 515 passengers who flew on planes that did not recirculate air, 108 reported post-flight respiratory symptoms, while 112 of the 585 passengers on planes that did recirculate air reported such symptoms. Is there sufficient evidence to conclude that the proportion of passengers with post-flight respiratory symptoms differs for planes that do and do not recirculate air? Test the appropriate hypotheses using ? = 0.05. You may assume that it is reasonable to regard these two samples as being independently selected and as representative of the two populations of interest. (Use a statistical computer package to calculate the P-value. Use pdo not recirculate − pdo recirculate. Round your test statistic to two…

It has been found that 25.1% of men (Group 1) 20 years and older suffer from hypertension (high blood pressure) and 33.9% of women (Group 2) are hypertensive. A random sample of 164 of each gender was selected from recent hospital records, and the following results were obtained. Can you conclude that a higher percentage of women have high blood pressure? Use =0.05. Men: 42 patients had high blood pressure Women: 52 patients had high blood pressure   Required: Test Value Only the final answer should be rounded-off to TWO decimal places.