The article “Dynamics of Insulin Action in Hypertension: Assessment from Minimal ModelInterpretation of Intravenous Glucose Tolerance Test Data” (R. Burattini, M. Morettini, etal., Med Biol Eng Comput, 2011:831–841) compared levels of an insulin sensitivity index SIin patients with high blood pressure and patients with normal blood pressure. Ten patientswith high blood pressure had a mean value of 3.4 with a standard deviation of 0.6, and eightpatients with normal blood pressure had a mean value of 7.9 with a standard deviation of0.6. Units are 10−5 · min−1 · pmol−1. Find a 98% confidence interval for the difference inmean levels between those with high blood pressure and those with normal blood pressure.

Below is R output for a 2´2 bivariate table that cross-tabulates subjective social class (that is, the social class to which the respondent believes they belong) and how fundamentalist the respondent is in terms of their religion. Note that the relationship is statistically significant (X^2 = 38.99; p < .001). The  (lambda) statistic is reported below the table. What is its interpretation? How is the interpretation of lambda different or unique from phi and Cramér’s ?

Productivity is the key driver of wages and one of the most importantdeterminants of living standards. The British Chambers of Commercecommissioned research into understanding whether labour productivity in theautomotive manufacturing sector in England and Ireland were the same ordifferent. The researchers collected data on a random sample of 8 firms inEngland and 4 in Ireland and recorded productivity in units of value added (£)per hour. It is assumed that firm-level productivity has a normal distribution.The following data were collected:Ireland 47 56 43 68England 39 50 39 45 50 43 35 43(i) Set up appropriate null and alternative hypotheses and conduct a test ofthe hypotheses of equal mean productivity in Ireland and England at 5 percent significance level under the assumption of unknown but equalpopulation variances. Provide as much detail as possible on yourprocedures. Clearly show all your steps in testing and state your decision.Discuss the economic implications of your findings.…

widely used as dielectrics and coolants in electrical systems in the past. They were found to be a major environmental contaminant in the 1960s. In a study, the mean PCB content at each of thirteen sites was reported for the years 1982 and 1996 (from “The ratio of DDE to PCB concentrations in Great Lakes herring gull eggs and its use in interpreting contaminants data”, Journal of Great Lakes Research 24 (1): 12-31, 1998). The data are below.Site:12345678910111213198261.4864.4745.5059.7058.8175.9671.5738.0630.5139.7029.7866.8963.93199613.9918.2611.2810.0221.0017.3628.207.3012.809.4112.6316.8322.74(a) Which test would be more appropriate in this case: a t-test for the difference between two population means, or a paired t-test? Why?(b) Do the data provide sufficient evidence to support the claim that the mean PCB level has decreased in the region? Be sure to check all assumptions, write the null and alternative hypotheses, calculate the appropriate test statistic, calculate the p-value,…

A study is planned to investigate risk factors for sudden cardiac death. A cohort of men and women between the ages of 35 and 70 is enrolled and followed for up to 20 years. As part of the study, participants provide data on demographic and behavioral characteristics; they also undergo testing for cardiac function and provide blood samples to assess lipid profiles and other biomarkers. A new measure of inflammation is hypothesized to be related to sudden cardiac death. Describe its strengths and weaknesses.

During the spring of 1999, many fuel storage facilities in Serbia were destroyed by bombing. As a result, significant quantities of oil products were spilled and burned,resulting in soil pollution. The article “Mobility of Heavy Metals Originating from Bombing of Industrial Sites” (B. Škrbić, J. Novaković, and N. Miljević, Journal of Environmental Science and Health, 2002:7–16) reports measurements of heavy metal concentrations at several industrial sites in June 1999, just after the bombing, and again in March of 2000. At the Smederevo site, on the banks of the Danube River, eight soil specimens taken in 1999 had an average lead concentration (in mg/kg) of 10.7 with a standard deviation of 3.3. Four specimens taken in 2000 had an average lead concentration of 33.8 with a standard deviation of 0.50. Find a 95% confidence interval for the increase in lead concentration between June 1999 and March 2000.

A randomized controlled trial was conducted to determine whether treatment with daily aspirin was more effective than placebo at preventing myocardial infarction (MI) (within 5 years).   A total of 140 out of 11,140 subjects in the aspirin group experienced an MI, while 240 out of 11,040 subjects in the placebo group experienced an MI.  The relative risk of MI comparing aspirin to placebo was calculated to be 0.58, and its 95% confidence interval ranged from 0.47 to 0.71.  Which of the following can be concluded from these results?   Question 4 options:   On average, the risk of MI among subjects who used aspirin was 0.58 times the risk of MI among those on placebo.   On average, aspirin reduced the risk of MI in this population by 58% when compared to placebo.   Aspirin is almost certainly harmful to this population.   Compared to placebo, aspirin did not reduce the risk of MI by a statistically significant amount.