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The drug diflunisal is used to treat mild to moderate pain due to osteoarthritis (OA) and rheumatoid arthritis (RA). The ocular effects of diflunisal had not been considered until a study was conducted on its effect on intraocular pressure in glaucoma patients who were already receiving maximum therapy for glaucoma [5].
Compute 95% CIs for the
Suppose the change (mean ± sd ) in intraocular pressure after administration of diflunisal (follow-up – baseline) among 10 patients whose standard therapy was methazolamide and topical glaucoma medications was −1.6 ± 1.5 mm Hg. Assess the statistical significance of the results.
The change in intraocular pressure after administration of diflunisal among 30 patients whose standard therapy was topical drugs only was −0.7 ± 2.1 mm Hg. Assess the statistical significance of these results.
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Fundamentals of Biostatistics
- The average value of the residuals isarrow_forwardRetinitis pigmentosa (RP) is a hereditary ocular diseasein which patches of pigment appear on the retina, potentially resulting in substantial vision loss and in somecases complete blindness. An important issue is how fastthe subjects decline. Visual field is an important measureof area of vision, which is measured in degree2. A visualfield area for a normal person is around 11,000 degree2.The longitudinal data in Table 11.29 were provided by anindividual patient.Table 11.29 Longitudinal visual field data forone RP patientTime Visual field area lnVisit (yr) (degree2) (visual field area)1 0 3059 8.032 1 3053 8.023 2 1418 7.264 3 1692 7.435 4 1978 7.596 5 1567 7.367 6 1919 7.568 7 1998 7.609 11 1648 7.4110 13 1721 7.4511 15 1264 7.14mean 6.09 1938 7.532sd 4.97 597 0.280Suppose the rate of change of ln (visual field) is a linearfunction of follow-up time.11.103 Write down a linear regression model that summarizes this relationship.11.104 Fit the regression line using the method of…arrow_forwardRetinitis pigmentosa (RP) is a hereditary ocular diseasein which patches of pigment appear on the retina, potentially resulting in substantial vision loss and in somecases complete blindness. An important issue is how fastthe subjects decline. Visual field is an important measureof area of vision, which is measured in degree2. A visualfield area for a normal person is around 11,000 degree2.The longitudinal data in Table 11.29 were provided by anindividual patient.Table 11.29 Longitudinal visual field data forone RP patientTime Visual field area lnVisit (yr) (degree2) (visual field area)1 0 3059 8.032 1 3053 8.023 2 1418 7.264 3 1692 7.435 4 1978 7.596 5 1567 7.367 6 1919 7.568 7 1998 7.609 11 1648 7.4110 13 1721 7.4511 15 1264 7.14mean 6.09 1938 7.532sd 4.97 597 0.280Suppose the rate of change of ln (visual field) is a linearfunction of follow-up time.11.103 Write down a linear regression model that summarizes this relationship.arrow_forward
- Overproduction of uric acid in the body can be an indication of cell breakdown. This may be an advance indication of illness such as gout, leukemia, or lymphoma.+ Over a period of months, an adult male patient has taken eleven blood tests for uric acid. The mean concentration was x = 5.29 mg/dl. The distribution of uric acid in healthy adult males can be assumed to be normal, with o = 1.87 mg/dl. (a) Find a 95% confidence interval for the population mean concentration of uric acid in this patient's blood. What is the margin of error? (Round your answers to two decimal places.) lower limit upper limit margin of error (b) What conditions are necessary for your calculations? (Select all that apply.) o is known o is unknown normal distribution of uric acid O uniform distribution of uric acid On is large (c) Interpret your results in the context of this problem. O We are 5% confident that the true uric acid level for this patient falls within this interval. O We are 95% confident that the…arrow_forwardCaptopril is a drug designed to lower systolic blood pressure. When subjects were treated with this drug, their systolic blood pressure readings (in mm Hg) were measured before and after the drug was taken. Results are given in the accompanying table (based on data from “Essential Hypertension: Effect of an Oral Inhibitor of Angiotensin-Converting Enzyme”, by MacGregor et al., BMJ, Vol. 2). Using a 0.01 significance level, is there sufficient evidence to support the claim that captopril has an effect on systolic blood pressure? i) Use the Wilcoxon signed-ranks test to conduct the required test without using "wilcox.test" function in R. Please state the hypothesis, provide the p-value, and the conclusion in the context of the problem. ii) Use the Wilcoxon signed-ranks test to conduct the required test using "wilcox.test" function in R. Please present a screenshot of the R output of your call to the function wilcox.test. iii) Would you recommend the Wilcoxon signed-ranks test over the…arrow_forwardDo wearable devices that monitor diet and physical activity help people lose weight? Researchers had 237 subjects who were already involved in a program of diet and exercise use wearable technology for 24 months. They measured their weight (in kilograms) before using the technology and 24 months after using the technology. The 237 differences in weight (weight after 24 months minus weight before using the wearable technology) had x = -3.5 and s = 7.8. Let u be the mean weight difference. 41 John M. Jakicic et al., "Effect of wearable technology combined with a lifestyle intervention on long-term weight loss, the IDEA randomized clinical trial," JAMA, 316, 2016, pp. 1161-1171. O Macmillan Learning " What is the test statistic? Give your answer to three decimal places. What is the P-value? The P-value is between 0.01 and 0.05. The P-value is less than 0.0005. O The P-value is between 0.0005 and 0.01. The P-value is greater than 0.05.arrow_forward
- Overproduction of uric acid in the body can be an indication of cell breakdown. This may be an advance indication of illness such as gout, leukemia, or lymphoma.+ Over a period of months, an adult male patient has taken eleven blood tests for uric acid. The mean concentration was x = 5.31 mg/dl. The distribution of uric acid in healthy adult males can be assumed to be normal, with o = 1.93 mg/dl. (a) Find a 95% confidence interval for the population mean concentration of uric acid in this patient's blood. What is the margin of error? (Round your answers to two decimal places.) lower limit upper limit margin of error (b) What conditions are necessary for your calculations? (Select all that apply.) a is unknown On is large O uniform distribution of uric acid normal distribution of uric acid a is known (c) Interpret your results in the context of this problem. O We are 5% confident that the true uric acid level for this patient falls within this interval. O The probability that this…arrow_forwardCaptopril is a drug designed to lower systolic blood pressure. When subjects were treated with this drug, their systolic blood pressure readings (in mm Hg) were measured before and after the drug was taken. Results are given in the accompanying table (based on data from "Essential Hypertension: Effect of an Oral Inhibitor of Angiotensin-Converting Enzyme," by MacGregor et al., British Medical Journal, Vol. 2). Using a 0.01 significance level, is there sufficient evidence to support the claim that captopril has an effect on systolic blood pressure?arrow_forwardDoes the potency of drug reduce after one year in storage? To test this, researchers plan to compare the average potency of a sample of recently produced bottles of the drug with the average potency of a sample of bottles of the drug that have been stored for a year. They will test for evidence that the mean potency score for the fresh drug (µ1) is higher than the mean potency score for the stored drug (µ2). Based on the information provided, which of the following sets of hypotheses is appropriate for the test? Hint: We first cover inference for a difference in means in Section 6.4. Select one: a.H0: μ1 - μ2 ≤ 0, Ha: μ1 - μ2 = 0 b.H0: μ1 - μ2 = 0, Ha: μ1 - μ2 > 0 c.H0: μ1 - μ2 = 0, Ha: μ1 - μ2 < 0 d.H0: μ1 - μ2 = 0, Ha: μ1 - μ2 ≠ 0arrow_forward
- A medical student at a community college in city Q wants to study the factors affecting the systolic blood pressure of a person (Y) Generally, the systolic blood pressure depends on the BMI of a person (B) and the age of the person A. She wants to test whether or not the BMI has a significant effect on the systolic blood pressure, keeping the age of the person constant. For her study, she collects a random sample of 125 patients from the city and estimates the following regression function: Y= 15.50 + 0..90B+1.15A. (0.55) (0 40) The test statistic of the study the student wants to conduct (Ho: B, = 0 vs. H, B, #0), keeping other variables constant is. (Round your answer to two decimal places.) At the 5% significance level, the student will ▼ the null hypothesis. Keeping BMIl constant, she now wants to test whether the age of a person (A) has no significant effect or a positive effect on the person's systolic blood pressure. So, the test statistic associated with the one-sided test the…arrow_forwardCheck my An airline's data indicate that this past year, the average time it takes to board their flights is 45 minutes. The airline is considering changing their boarding procedures to reduce the boarding time for travelers. The new procedures were implemented and the boarding times for a random sample of 22 customers was taken to determine if there was a statistically significant decrease at in boarding times a= 0.10 with z = - 0.89 and t = . 1.07. What is the decision?arrow_forwardTotal cholesterol levels for middle aged men (aged 55 – 64) follow approximately a normal distribution with mean, u = 222 mg/dLi and standard deviation, o= 37 mg/dLi. Those with a total cholesterol of 240 mg/dLi or higher have “high" cholesterol (and have twice the risk of coronary heart disease as someone with a total cholesterol less than 200 mg/dLi) Find the Z-score (standard score) for an observation of 300 mg/dl. Round up to two decimal space.arrow_forward
- Calculus For The Life SciencesCalculusISBN:9780321964038Author:GREENWELL, Raymond N., RITCHEY, Nathan P., Lial, Margaret L.Publisher:Pearson Addison Wesley,Glencoe Algebra 1, Student Edition, 9780079039897...AlgebraISBN:9780079039897Author:CarterPublisher:McGraw Hill