Echinacea is widely used as an herbal remedy for thecommon cold, but does it work? In a double-blindexperiment, healthy volunteers agreed to be exposed tocommon-cold-causing rhinovirus type 39 and have theirsymptoms monitored. The volunteers were randomlyassigned to take either a placebo or an echinaceasupplement daily for 5 days following viral exposure.Among the 103 subjects taking a placebo, 88 developed acold, whereas 44 of the 48 subjects taking echinacea1developed a cold. Give the 95% plus four confidence interval for thedifference in proportions (p₁ - p₂) of individualsdeveloping a cold after viral exposure between theechinacea treatment and the placebo. Let p₁ represent theproportion for the placebo patient population and p2represent the proportion for the echnaceapatient population.Provide the lower bound and upper bound of the confidenceinterval to three decimal places.Lower bound:Upper bound:

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Answered: Echinacea is widely used as an herbal…

MATLAB: An Introduction with Applications

6th Edition

ISBN:9781119256830

Author:Amos Gilat

Publisher:Amos Gilat

Chapter1: Starting With Matlab

Section: Chapter Questions

Problem 1P

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1 of Question Help ▼ A study conducted in Uganda and Kenya looked at heterosexual couples in which one of the partners was HIV-positive and the other was not. The person in each couple who was not HIV-positive was randomly assigned to one of three study regimens: tenofovir (TDF), combination tenofovir-emtricitabine (TDF-FTC), or placebo and was followed for up to 36 months. Fifteen of the 1415 people assigned to TDF became positive for HIV, as did 12 of the 1463 assigned to TDF-FTC and 52 of the 1615 assigned to the placebo. Complete parts (a) through (c) below. 2 of 2 H: Treatment and HIV status have non-equal proportions. O D. Ho: Treatment and HIV status are independent. H Treatment and HIV status are associated. Calculate the chi-square test statistic. 0 of 2 x² = (Round to two decimal places as needed.) Determine the p-value. 1 of 1 p-value = (Round to three decimal places as needed.) What is the conclusion for this test? O A. Reject Ho and conclude that the treatment and HIV…
5
Peanut Allergies. In the article “Food Allergy Advice May Be Peanuts” (Science News, Vol. 174, No. 12, pp. 8–9), N. Seppa reports that early exposure to peanuts seems to lessen the risk of nut allergy. Of 4000 Jewish children sampled in Britain, 1.85% had peanut allergies; and of 4600 Jewish children sampled in Israel, where early peanut consumption is more common, 0.17% had peanut allergies. The researcher chose Jewish children in both countries to limit genetic differences between groups. a. Is this study descriptive or inferential? b. Is this study observational or experimental?
Need help with C - H
A social psychologist studying mass communication randomly assigned 77 volunteers to one of two experimental groups. Fifty-seven were instructed to get their news for a month only from television, and 20 were instructed to get their news for a month only from the Internet. After the month was up, all participants were tested on their knowledge of several political issues. The researcher simply predicted that there is some kind of difference. These were the results of the study. TV group: Mty = 22, S, = 2; Internet group: M, = 26.2, s = 3. The pooled variance, rounded to four decimal places, is 2.2533. Complete parts (a) and (b) below. (a) Figure the estimated effect size for this study. Let the TV group be sample 1 and let the Internet group be sample 2. The estimated effect size for this study is
In a 2009 study, a team of researchers recruited 38 men and divided them randomly into two groups - treatment or control. The also recruited 38 women and they randomly placed half the participants into the treatment group and the other half into the control group. One group was given 25 grams of chia seeds twice a day, and the other was given a placebo. The subjects volunteered to be a part of the study. After 12 weeks, the scientists found no significant difference between the groups in appetite or weight loss. Which of the following is true. (i) This is an observational study (ii) Blinding is used in this study because subjects in the control group recieved a placebo, so that htey were blinded to the treatment they recieved. (iii) We can safely generalize the conclusion (that chia seeds have no significant effect on appetite or weight loss) from the participants to the population at large because randomization is used when assigning participatns to groups.
The NIH is funding a trial for a new antidepressant drug. A sample of 1000 people with severe depression are recruited and, at baseline, are given a questionnaire asking about their demographic characteristicsand their mental health. They are then randomly assigned to one of two groups. The treatment group receives the new antidepressant, a pill that must be taken twice a day. The control group receives a placebo pill containing nothing medically active, which must also be taken twice a day. After 10 weeks, researchers locate the individuals and ask them to fill out a questionnaire again assessing their mental health. At the end of the study, researchers find no statistically significant difference in the mental health of the treatment and control groups. Q: Should we be concerned about unbalanced groups here? Is it possible to empirically explore whether this is a problem for this study?
Angioplasty is a medical procedure in which an obstructed blood vessel is widened. In some cases, a wire mesh tube, called a stent, is placed in the vessel to help it remain open. A study was conducted to compare the effectiveness of a bare metal stent with one that has been coated with a drug designed to prevent reblocking of the vessel. A total of 5319 patients received bare metal stents, and of these, 848 needed treatment for reblocking within a year. A total of 1122 received drug-coated stents, and 142 of them required treatment within a year. Can you conclude that the proportion of patients who needed retreatment differs between those who received bare metal stents and those who received drug-coated stents? Let p1 denote the proportion of patients with bare metal stents who needed retreatment and p2 denote the proportion of patients with drug-coated stents who needed retreatment. Use the =α0.10 level of significance and the P -value method with the…
Trichotillomania is a psychiatric illness that causes its victims to have an irresistible compulsion to pull their own hair. Two drugs were compared as treatments for trichotillomania in a study involving 13 women. Each women took clomipramine during one time period and desipramine during another time period in a double-blind experiment. Scores on a trichotillomania-impairment scale, in which high scores indicate greater impairment, were measured on each women during time period. The average of the 13 measurements for clomipramine was 6.2; the average of the 13 measurements for desipramine as 4.2. (a) A paired t test was used to test whether the mean difference between these two drugs is 0, resulting in a test statistics t∗ = 2.47. Find the sample standard deviation Sd. (b) Find a 95% confidence interval for the mean difference between the two drugs and give the conclusion.
In randomized, double-blind clinical trials of a new vaccine, children were randomly divided into two groups. Subjects in group 1 received the new vaccine while subjects in group 2 received a control vaccine. After the second dose, 125 of 746 subjects in the experimental group (group 1) experienced fever as a side effect. After the second dose, 82 of 627 of the subjects in the control group (group 2) experienced fever as a side effect. Does the evidence suggest that a higher proportion of subjects in group 1 experienced fever as a side effect than subjects in group 2 at the a= 0.01 level of significance? Find the test statistic for this hypothesis test. (Round to two decimal places as needed.)
A researcher is creating a new treatment protocol for Myelodysplastic Syndrome (MDS), a form of preleukemia. Following the old treatment protocol, 28% of patients with MDS will develop leukemia within 5 years of MDS diagnosis. He believes his new treatment protocol will lead to fewer MDS patients developing leukemia. He takes a random sample of 100 individuals on his new treatment protocol. Of these 100 individuals, 20 develop leukemia within 5 years of MDS diagnosis. In questions 8-9, create a 98% confidence interval for the true proportion of all MDS patients on this new treatment who will develop leukemia within 5 years of MDS diagnosis. What is the confidence interval? Do not round your answer. What is the interpretation of your confidence interval?
In a study on the effect of an oral rinse on plaque buildup on teeth, sixteen people whose teeth were thoroughly cleaned and polished were randomly assigned to two groups of eight subjects each. Both groups were assigned to use oral rinses (no brushing) for a 2-week period. Group 1 used a rinse that contained an antiplaque agent. Group 2, the control group, received a similar rinse except that the rinse contained no antiplaque agent. A measure of plaque buildup was recorded at 14 days with means and standard deviations for the two groups shown in the table. Control Group Antiplaque Group Sample Size 8 8. Mean 1.22 0.77 Standard Deviation 0.33 0.33 n USE SALT (a) State the null and alternative hypotheses that should be used to test the effectiveness of the antiplaque oral rinse. O Ho: (H, - H2) = 0 versus H: (, - H2) 0 O Ho: (H1 - H2) = 0 versus H,: (H, - H2) > 0 O Ho: (H1 - H2) = 0 versus H.: (4, - H2) # 0 (b) Do the data provide sufficient evidence to indicate that the oral…

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