2) (9.2) A study was conducted that asked adult Americans, "How many hours have you worked in the previous week?" Of the respondents, 1100 participants resulted in a mean of 42.4 hours and a standard deviation of 1.3 hours. Construct a 95% confidence interval for the population mean number of hours worked by adult Americans in the previous week.
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- 4. A surgeon is experimenting with a new technique for implanting artificial blood vessels. Using this technique, the mean time for clotting of artificial blood vessel has been 32.5 days with a standard deviation of 2.6 days. How long would a vessel have to stay open to be in the 95th percentile?An important measure in the study of contagious infectious diseases is the number of cases directly generated by one previous case. Jessica is an epidemiologist studying the spread of an infectious disease in her country. She claimed that the mean number of cases directly generated by one previous case is now greater than 1.2. A study of 12 randomly selected cases of the disease is conducted and finds the sample mean number of cases directly generated by one previous case to be 1.5 with a sample standard deviation of 0.7. Assume that the population of the number of cases directly generated by one previous case is approximately normally distributed. Complete the parts below to perform a hypothesis test to see if there is enough evidence, at the 0.10 level of significance, to support the claim that u, the mean number of cases directly generated by one previous case, is greater than 1.2. (a) State the null hypothesis H, and the alternative hypothesis H, that you would use for the test.…A hypertension trial is mounted and 12 participants are randomly assigned to receive either a new treatment or a placebo. Each participant takes the assigned medication and their systolic blood pressure (SBP) is recorded after 6 months on the assigned treatment. The data are as follows. Placebo New Treatment 132 114 143 119 148 121 144 124 155 126 160 128 Is there a difference in mean SBP between treatments? Run the test at a 5% level of significance. Give each of the following to receive full credit : 1) the appropriate null and alternative hypotheses; 2) the appropriate test; 3) the decision rule; 4) the calculation of the test statistic ; and 5) your conclusion including a comparison to alpha or the critical value. You MUST show your work to receive full credit. Partial credit is available.
- A magazine reports that women trust recommendations from a particular social networking site more than recommendations from any other social network platform. But does trust in this social networking site differ by gender? The following sample data show the number of women and men who stated in a recent sample that they trust recommendations made on this particular social networking site. Women Men Sample 150 170 Trust RecommendationsMade on the social networking site 117 102 (a) What is the point estimate of the proportion of women who trust recommendations made on this particular social networking site? (b) What is the point estimate of the proportion of men who trust recommendations made on this particular social networking site? (c) Provide a 95% confidence interval estimate of the difference between the proportion of women and men who trust recommendations made on this particular social networking site. (Round your answers to four decimal places.) toa simple random sample of 9 college freshmen were asked how many hour of sleep they typically got per night. The results were 8.5,6.5,8,9,6,7.5,24,8.5,9.5. Elminate the outlier, then consturct a 90% confidence interval for the mean amount of sleep from the remaining values.2. A sample of six college basketball player had an average weight of 217 pounds with a sample standard deviation of 10 pounds. Find the 95% confidence interval of the true mean weight of all basketball player.
- According to a recent article about individuals who have credit cards, the mean number of cards per person with credit cards is 4.5. To test this result a random survey of 60 individuals who have credit cards was conducted. The survey only includes the number of credit cards per participant. The results of the survey are attached below. (a) What is the variable of interest in this study? Is it qualitative or quantitative? (b) Do the results of the survey imply that the mean number of cards per individual is less than 4.5? Use the a = 0.05 level of significance. E Click the icon to view the data from the survey. (a) What is the variable of interest in this study? Is it qualitative or quantitative? The variable of interest is number of credit cards.It is a quantitative variable. (b) Do the results of the survey imply that the mean number of cards per individual is less than 4.5? Use the a = 0.05 level of significance. State the null and alternative hypotheses. Họ: H = 4.5 < 4.5 H1: H…Construct a 95% confidence interval for the true average number of visitors per day to ashopping mall if it was found that on 30 randomly selected days, the average number of visitors per day was 100.25, with a standard deviation of 7.5. Interpret your answer.The mean potassium content of a popular sports drink is listed as 132 mg in a 32-oz bottle. Analysis of 24 bottles indicates a sample mean of 131.2 mg. (a) State the hypotheses for a two-tailed test of the claimed potassium content.. a. Ho: μ= 132 mg vs. H₁: b. He: ≤132 mg vs. H₁: c. He: ≥132 mg vs. H₁: Oa Ob Oc (b) Assuming a known standard deviation of 2.1 mg, calculate the z test statistic to test the manufacturer's claim. (Round your answer to 2 decimal places. A negative value should be indicated by a minus sign.) Test statistic 132 mg >132 mg <132 mg (c) At the 2 percent level of significance (a = .02) does the sample contradict the manufacturer's claim? Decision Rule: Reject Ho
- Prices of basic commodities are often greatly affected by typhoons. During the aftermath of recent typhoon, the prices of tilapia were reported to have been sold at ₱20 – ₱25 more per kilogram at local wet markets. However, the price was back to its normal mean price at ₱100 per kilo one week after. If a random sample of 10 tilapia sales transactions from local wet markets have prices (in pesos per kilo) of 107, 115, 130, 95, 100, 105, 98, 116, 104, 100. Assuming that the tilapia prices are normally distributed, is there sufficient evidence to say that the mean price of tilapia in these markets is greater than ₱100? Use a 0.05 level of significance. State the null and alternative hypotheses: Ho: ________ (symbols) Ho: _______________________________ (statement) Ha: _________ (symbols) Ha: _______________________________ (statement)A sports news station wanted to know whether people who live in the North or the South are bigger sports fans. For its study, 121 randomly selected Southerners were surveyed and found to watch a mean of 4.6 hours of sports per week. In the North, 176 randomly selected people were surveyed and found to watch a mean of 3.2 hours of sports per week. Find a 90% confidence interval for the true difference between the mean numbers of hours of sports watched per week for the two regions if the South has a population standard deviation of 1.6 hours per week and the North has a population standard deviation of 1.4 hours per week. Let Population 1 be people who live in the South and Population 2 be people who live in the North. Round the endpoints of the interval to one decimal place, if necessary. Lower endpoint: Upper endpoint:Suppose we have only ten scores representing the ages (in years) of randomly selected U.S. commercial aircraft. The average age of the ten aircraft is 14.25 years and the sample standard deviation is 9.349 years. Construct a 95% confidence interval for the mean age of all U.S. commercial aircraft. I would appreciate to see what formulas you use and the work through because I messed up.