In a recent questionnaire about homeownership, a random sample of 545 homeowners were asked about fixed and adjustable-rate mortgages, and 268 reported that they have an adjustable-rate mortgage. What value of z should be used to calculate a confidence interval with a 95% confidence level? z0.10 z0.05 z0.025 z0.01 z0.005 1.282 1.645 1.960 2.326 2.576

The drug Viagra became available in the U.S. in May 1988, in the wake of an advertising campaign that was unprecedented in scope and intensity. A Gallup poll found that by the end of the first week of May, 643 out of 1,005 adults were aware that Viagra was an impotency medication.   a) Is the sample size large enough to compute a confidence interval for the proportion of adults who were aware that Viagra was an impotency medication after the first week of May? Yes, because more than 10 adults were not aware of Viagra Yes, because the sample size is greater than 30 Yes, because more than 10 adults were aware of Viagra Yes, because both np̂ and n(1-p̂) are greater than 10   b)Using the information from questions 1-3, suppose that p̂ is 0.40 and the standard error of p̂ is 0.10. Compute a 90% confidence interval for the proportion of adults that were aware of Viagra. (0.2355, 0.5645) (0.3, 0.5) (0.2355, 0.4) (0.3, 0.4)

Consider the following results for independent samples taken from two populations. Sample 1 Sample 2 n1 = 400 n2= 200 p1= 0.46 p2= 0.34 a.  What is the point estimate of the difference between the two population proportions (to 2 decimals)?  b.  Develop a 90% confidence interval for the difference between the two population proportions (to 4 decimals). Use z-table.  to   c.  Develop a 95% confidence interval for the difference between the two population proportions (to 4 decimals). Use z-table.  to

A research group studying cell phone habits asked the question “Do you ever use your cell phone to make a payment at a convenience store?” to people selected from two random samples of cell phone users. One sample consisted of older adults, ages 35 years and older, and the other sample consisted of younger adults, ages 18 years to 34 years. The proportion of people who answered yes in each sample was used to create a 95 percent confidence interval of (0.097,0.125)(0.097,0.125) to estimate the difference (younger minus older) between the population proportions of people who would answer yes to the question. Which of the following is the best description of what is meant by 95 percent confidence?     In repeated random sampling with the same sample size, approximately 95% of the sample proportions from the younger group will be between 0.097 and 0.125 greater than the sample proportion from the older group. A In repeated random sampling with the same sample size,…

1. A recent survey showed that from a sample of 500 packages delivered by a Postal Service, 480were delivered on time. a) Construct a 95% confidence interval for the proportion of all packages that are deliveredon time by the Postal Service.

A researcher surveys 50 individuals in Smithville and 40 in Amherst, finding that 30% of smithville residents moved last year, while only 22% of Amherst residents did. Is there enough evidence to conclude that mobility rates in the two communities differ? Use a two-tailored alternative, and a=0.10. Again, find the p-value and a 90% confidence interval for the difference in proportions

For a sample of 400 correctional officers at Lucasville State Prison, a researcher believes there is a relationship between “years on the job” and “willingness to help raise money for adult charities.” Using the following data, test the null hypothesis at the .01 level of significance that willingness to help raise donations does not differ by length of service as a correctional officer.  In so doing, identify: (1) the research and null hypothesis, (2) the critical value needed to reject the null, (3) the decision that you made upon analyzing the data, and (4) the conclusion you have drawn based on the decision you have made.

The following chloride (mmol/L) results were obtained using a new analyzer: 106 111 104 106 112 110 115 127 83 110 108 109 83 119 105 106 108 114 120 100 107 110 109 102 Using the data given, calculate and record the mean, SD and the confidence intervals to plot your Levey-Jennings control chart. Show your solutions and plot a LJ chart. After plotting your chart, are the values all in control/accepted? If not, which value should be rejected? What rule is violated? What kind of error more likely contributed to the violation? Please just plot.

wo groups of men, those dressed as Luke Skywalker and those dressed as storm troopers were measured for height in inches. Data in table below: Lukes Storm Troopers xbar=67 xbar = 70 n=14 n=11 sd = 1 sd = 3 Using this data, and the assumption that the population variances are equal, give a 90% confidence interval for mu (storm troopers) - mu (lukes) = μS - μL