Practice Problem 3 - Chi-squared Test for Independence (4 points) A randomized trial is designed to evaluate the effectiveness of a newly developed pain reliever to reduce pain in patients following joint replacement surgery. Patients were asked their level of pain then given the designated treatment. After 30 minutes, they were asked to rate their pain gain. Results were categorized as meaningful reduction (3+ points) or no meaningful reduction (<3 points). The table below shows the data collected. Is there a relationship between the type of treatment given and pain reduction? New pain reliever Higher dose of new pain reliever Standard pain reliever Total Meaningful reduction (3+ points) 21 32 11 64 No meaningful reduction (<3 points) 29 18 39 86 Total 50 50 50 150
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- Null hypothesis (H0): There is no relationship between the type of treatment given and pain reduction. - Alternative hypothesis (Ha): There is a relationship between the type of treatment given and pain reduction. Show more…
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Multiple Choice To test the effectiveness of a new pain medication, a random sample of 50 people with chronic pain is taken. n1=30 of the people are randomly assigned to a placebo group and the remaining n2=20 are assigned to the treatment group. Each person takes their respective pills (placebo or actual pain medication) and two hours later, they are asked to rate their pain level on a scale of 1 to 10. Given the following summary information, determine the Determine the value of the test statistic for the pooled t-test. xbar 1 = 7.9, s1 = 3.5, xbar 2= 5.3, s2 =2.0, sp = 2.997 a. t = 3.20 b. t = 3.34 c. t = 2.57 d. t = 3.01 Multiple Choice Find the value a such that P( 0 < Z < a ) = 0.2224. Enter your answer two decimal place a. 0.77 b. 0.59 c. 0.62 d. 0.73
Rosina D.
In a study to compare the effects of two pain relievers it was found that of n1 = 250 randomly selected individuals who used the first pain reliever, 0.93 indicated that it relieved their pain. Of n2 = 600 randomly selected individuals who used the second pain reliever, 0.96 indicated that it relieved their pain: (a) Find a 99% confidence interval for the difference in the proportions experiencing relief from pain for these two pain relievers. (Use p1 - p2. Round your answers to three decimal places.) 0.346 to 0.346 (b) Based on the confidence interval in part (a), is there sufficient evidence to indicate a difference in the proportions experiencing relief for the two pain relievers? Explain. Since the value p1 - p2 = 0 is in the confidence interval, it is possible that p1 = p2. You should not conclude that there is a difference in the population proportion of people who experience pain relief when using one pain reliever or the other. You may need to use the appropriate appendix table or technology to answer this question.
Lucas F.
Assume that the two samples are independent simple random samples selected from normally distributed populations, and do not assume that the population standard deviations are equal. Do the following: a. Test the given claim using the PÂvalue method or critical value method. b. Construct a confidence interval suitable for testing the given claim. People spend around $5 billion annually for the purchase of magnets used to treat a wide variety of pains. Researchers conducted a study to determine whether magnets are effective in treating back pain. Pain was measured using the visual analog scale, and the results given below are among the results obtained in the study (based on data from “Bipolar Permanent Magnets for the Treatment of Chronic Lower Back Pain: A Pilot Study,” by Collacott, Zimmerman, White, and Rindone, Journal of the American Medical Association, Vol. 283, No. 10). Use a 0.05 significance level to test the claim that those treated with magnets have a greater mean reduction in pain than those given a sham treatment (similar to a placebo). Does it appear that magnets are effective in treating back pain? Is it valid to argue that magnets might appear to be effective if the sample sizes are larger? Reduction in Pain Level After Magnet Treatment: n = 20 , x ? = 0.49 , s = 0.96 Reduction in Pain Level After Sham Treatment: n = 20 , x ? = 0.44 , s = 1.4
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