Dexamethasone and IQ. In the paper “Outcomes at School Age After Postnatal Dexamethasone Therapy for Lung Disease of Prematurity” (New England Journal of Medicine, Vol. 350, No. 13, pp. 1304–1313), T. Yeh et al. studied the outcomes at school age in children who had participated in a double-blind, placebo-controlled trial of early postnatal dexamethasone therapy for the prevention of chronic lung disease of prematurity. All of the infants in the study had had severe respiratory distress syndrome requiring mechanical ventilation shortly after birth. On the WeissStats site, we provide the school-age IQs of the 74 children in the control group, based on the study results. Use the technology of your choice to do the following. a. Obtain a normal probability plot, boxplot, histogram, and stemand-leaf diagram of the data. b. Based on your results from part (a), can you reasonably apply one-standard-deviation χ2-procedures to the data? Explain your reasoning. c. Overall, IQs of school-age…

An article from the American Journal of Public Health  reports the results from a randomized study designed to evaluate the efficacy of an intervention targeted to Hispanic/Latino men who identify as gay, bi-sexual or other men who have sex with men (MSM).   A representative sample of 254 such men was randomized to be in either the intervention group (n=152, with 141 ultimately participating in the study) or the control group (n=152,  with 147 ulitmately participating in the study). The primary outcome under study getting tested for HIV within the six-months following group assignment (randomization) among those who had been sexually active in this same six-month follow-up period. At six months of follow-up, 141 subjects in the intervention group reported having had sex (with men and/or women) since randomization.  Of these 141 men, 114 had been tested for HIV since being randomized.    At six months of follow-up, 147 subjects in the control group reported having had sex (with men…

The article “Treadmill Exercise and Resistance Training in Patients With Peripheral Arterial Disease With and Without Intermittent Claudication. A Randomized Controlled Trial” (M. McDermott, P. Ades, et al., Journal of the American Medical Association, 2009:165–174) reported the results of a study to determine whether treadmill exercise could improve the walking ability of patients suffering from claudication, which is pain caused by insufficient blood flow to the muscles of the legs. A sample of 48 patients walked on a treadmill for six minutes every day. After six months, the mean distance walked in six minutes was 348 meters, with a standard deviation of 80 m. For a control group of 46 patients who did not walk on a treadmill, the mean distance was 309 m with a standard deviation of 89 m. Can you conclude that the mean distance walked for patients using a treadmill is greater than the mean for the controls? Use the α = 0.05 level of significance.

please help me out. show full working out for better understanding      Hereditary hemochromatosis (HH) is a recessively inherited genetic disorder resulting from mutations in the HFE gene. There are several possible mutations of different degrees of importance but the disease expresses itself only when at least 2 arepresent in any one individual. A blood analysis was performed on 3,000 blood samples from newborn babies of Caucasian descent in the state of Michigan, USA. The results showed that 163 of those sampled carried two mutations in the HFE gene. a. What is the proportion in the sample that carry the two mutations of the HFE gene? b. Calculate the 95% confidence interval for the proportion of this population that carries two mutations in the HFE Check the data for the necessary conditions and show full working. c. Interpret your interval in context d. If the researcher wanted to halve (x ½) the margin of error in the confidence interval found, what sample size would be required…

A case–control study of patients on antihypertensive drugs related an increased risk of myocardial infarction (MI) for patients using calcium channel blockers (Psaty, et al.,1995). In this study, cases were antihypertensive drug patients who had suffered a first fatal or nonfatal MI through 1993, and controls were antihypertensive patients, matched by demographic factors, who had not suffered a MI. Among the comparisons reported were patients receiving calcium channel (CC) blockers (with and without diuretics) and patients receiving β–blockers (with and without diuretics). Results of numbers of patient by drug/MI status combination are given in Table 1. Compute the odds ratio of suffering MI (CC blockers relative to β–blockers), and the corresponding 95% CI. Does it appear that calcium channel blockers are associated with higher odds (and thus probability) of suffering MI than β –blockers?   Table 1: Observed cell counts for antihypertensive drug/MI data     Occurrence of…

A paper published in the Journal of Dermatology and Venereology reported that nickel allergy more likely to occur in women who report cosmetic dermatitis from using eye shadow. The researcher has taken two samples in their study from a similar population. In the first sample of 131 women with cosmetic dermatitis from using eye shadow, 12 were diagnosed with a nickel allergy. While in the second sample of 250 women with cosmetic dermatitis from using eye shadow, 25 were diagnosed with a nickel allergy. Compute a 95% confidence interval that is a closely related but simpler alternative to Wilson's Method for the first and the second samples for the proportion of women with cosmetic dermatitis from using eye shadow who have a nickel allergy. (i) (ii) Compare the two confidence intervals you compute in (i). (i) Suppose you are informed that the true proportion of women diagnosed with a nickel allergy is 0.12. Explain it refers to which group.

Researchers suspect that drinking tea might enhance the production of interferon gamma, a molecule that helps the immune system fight bacteria, viruses, and tumors. A recent study involved 20 healthy people who did not normally drink tea or coffee. Ten of the participants were randomly assigned to drink five cups of tea a day, while 10 were asked to drink the same amount of coffee. After two weeks, blood samples were exposed to an antigen and production of interferon gamma were measured. The results are shown in the following table: Теа: 55 17 54 49 10 46 21 14 53 Coffee: 16 12 20 52 37 15 22 30 3 Let X ~ N(ux,o3) be the interferon gamma production for participants who drink tea and observations for the ten participants who drink tea are a random sample from X. Let Y ~ N(uy,o) be the interferon gamma production for participants who drink coffee and observations for the ten participants who drink coffee are a random sample from Y. Some R output that may help. > p1 qnorm(p1) [1] -2.326…

Suppose a study investigated the effects of vitamin A, vitamin C, and omega-3 fatty acids supplements on improving eye health and vision. 300 adults volunteered to take part in the study. In the study, participants were randomly assigned to one of 3 different levels of Vitamin A (Level A, Level B, or Level C) and randomly assigned to one of 2 different levels of Vitamin C (Level 1 or Level 2) and randomly assigned to one of 2 different levels of omega-3 fatty acid (Level I or Level II). a. Identify the subjects of the study. b. Identify the factor(s) for the study and the number of treatment level(s) for each factor. c. How many different treatment groups are there in this study?

A pathological video game user (PVGU) is a video game user that averages 31 or more hours a week of gameplay. According to the article “Pathological Video Game Use among Youths: A Two-Year Longitudinal Study” (Pediatrics, Vol. 127, No. 2, pp. 319–329) by D. Gentile et al., in 2011, about 9% of children in grades 3–8 were PVGUs. Suppose that, today, five youths in grades 3–8 are randomly selected. Let X represent the number of youths who are PVGUs. n =  p =  1 – p =  Prepare the probability distribution for the random variable X. Complete the following table. Round your answers to 4 decimal places e.g. 0.XXXX or .XXXX. X = x P(X=x) 0   1   2   3   4   5     ∑=1.0000∑=1.0000  Calculate the probability that EXACTLY three youths are PVGUs. Round your answers to 4 decimal places e.g. 0.XXXX or .XXXX. P(X = 3) =  Calculate the probability that AT LEAST two youths are PVGUs. Round your answers to 4 decimal places e.g. 0.XXXX or .XXXX. P(X ≥ 2) =  Calculate the…