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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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EBK FUNDAMENTALS OF BIOSTATISTICS
- 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, anadult male patient has taken eight blood tests for uric acid. The mean concentration was ?̅= 5.35mg/dl. The distribution of uric acid in healthy adult males can be assumed to be normal, with σ = 1.85 mg/dl.a. Find a 90% confidence interval for the population mean concentration of uric acid in this patient’s blood. What is the margin of error?b. Find a 99% confidence interval for the population mean concentration of uric acid in this patient’s blood. What is the margin of error? Compare the lengths of the confidence intervals for parts (a) and (b). As the confidence levelsincrease, do the confidence intervals increase in length?arrow_forwardUnfortunately, arsenic occurs naturally in some ground water.t A mean arsenic level of u = 8.0 parts per billion (ppb) is considered safe for agricultural use. A well in Texas is used to water cotton crops. This well is tested on a regular basis for arsenic. A random sample of 36 tests gave a sample mean of x = 6.7 ppb arsenic, with s = 3.0 ppb. Does this information indicate that the mean level of arsenic in this well is less than 8 ppb? Use a = 0.01. n USE SALT (a) What is the level of significance? State the null and alternate hypotheses. O Ho: H = 8 ppb; H,: u > 8 ppb O Ho: H = 8 ppb; H,: H + 8 ppb O Ho: H 8 ppb; H,: u = 8 ppb O Ho: H = 8 ppb; H,: µ 0.100 O 0.050 < P-value < 0.100 O 0.010 < P-value < 0.050 O 0.005 < P-value < 0.010 P-value < 0.005 Sketch the sampling distribution and show the area corresponding to the P-value. MacBook Pro escarrow_forwardOverproduction 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_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_forwardTotal plasma volume is important in determining the required plasma component in blood replacement therapy for a person undergoing surgery. Plasma volume is influenced by the o health and physical activity of an individual. Suppose that a random sample of 46 male firefighters are tested and that they have a plasma volume sample mean of x = 37.5 ml/kg (milliliters plasma per kilogram body weight). Assume that o = 7.80 ml/kg for the distribution of blood plasma. %3D (a) Find a 99% confidence interval for the population mean blood plasma volumne in male firefighters. 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.) the distribution of volumes is normal the distribution of volumes is uniform o is unknown n is large o is known (c) Interpret your results in the context of this problem. O The probability that this interval contains the true average…arrow_forwardA study was conducted assessing the effect of observer training on measurement of blood pressure based on NHANES data from 1999–2000 (Ostchega, et al., [1]). A goal was that the difference in recorded blood pressure between the observer and trainer be ≤ 2 mm Hg in absolute value. It was reported that the mean difference in systolic blood pressure (SBP) between observers and trainers (i.e., mean observer SBP minus trainer SBP) = mean (Δ) was 0.189 mm Hg with sd = 2.428 mm Hg. 1. If we assume that the distribution of Δ is normally distributed, then what % of (observer, trainer) pairs have a mean difference of ≥ 2 mm Hg in absolute value (i.e., either ≥ 2 mm Hg or ≤ −2 mm Hg)? 2. If we assume that the distribution of Δ is normally distributed, then what is the 90 percentile (i.e., the upper decile) and 10 percentile (i.e., the lower decile) of the distribution?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 8 blood tests for uric acid. The mean concentration was x = 5.35 mg/dl. The distribution of uric acid in healthy adult males can be assumed to be normal, with σ = 1.85mg/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? (b) What conditions are necessary for your calculations? (c) interpret your results in the context of this problem. (d)Sample size find the sample size necessary for a 95% confidence level maximal margin of error E=1.10 for the mean concentration of uric acid in this patient's blood.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_forwardOverproduction 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.t Over a period of months, an adult male patient has taken five blood tests for uric acid. The mean concentration was x = 5.40 mg/dl. The distribution of uric acid in healthy adult males can be assumed to be normal, with o = 1.85 mg/dl. (a) Find a 95% confidence interval for the population mean concentration of uric acid in this patient's blood. Wwhat 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.) V o is known O n is large O o is unknown V normal distribution of uric acid O uniform distribution of uric acid (c) Interpret your results in the context of this problem. O we are 95% confident that the true uric acid level for this patient falls within this interval. O The probability that…arrow_forward
- Spray drift is a constant concern for pesticide applicators and agricultural producers. The inverse relationship between droplet size and drift potential is well known. The paper "Effects of 2,4-D Formulation and Quinclorac on Spray Droplet Size and Deposition"t investigated the effects of herbicide formulation on spray atomization. A figure in a paper suggested the normal distribution with mean 1050 um and standard deviation 150 µm was a reasonable model for droplet size for water (the "control treatment") sprayed through a 760 ml/min nozzle. n USE SALT (a) What is the probability that the size of a single droplet is less than 1470 um? At least 950 µm? (Round your answers to four decimal places.) less than 1470 um at least 950 um (b) What is the probability that the size of a single droplet is between 950 and 1470 pm? (Round your answer to four decimal places.) (c) How would you characterize the smallest 2% of all droplets? (Round your answer to two decimal places.) The smallest 2% of…arrow_forwardOverproduction of uric acid in the body can be an indication of cell breakdown. This may be an advance indication of illness such gout, leukemia, or lymphoma.t Over a period of months, an adult male patient has taken twelve blood tests for uric acid. The mean concentration was x = 5.35 mg/dl. The distribution of uric acid in healthy adult males can be assumed to be normal, with o = 1.91 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 n is large O uniform distribution of uric acid O o is unknown O normal distribution of uric acid O o 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_forwardOverproduction 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.t Over a period of months, an adult male patient has taken thirteen blood tests for uric acid. The mean concentration was x = 5.28 mg/dl. The distribution of uric acid in healthy adult males can be assumed to be normal, with o = 1.91 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 n is large o is unknown normal distribution of uric acid uniform distribution of uric acid (c) Interpret your results in the context of this problem. We are 5% confident that the true uric acid level for this patient falls within this interval. The probability that this interval…arrow_forward
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