WMW Rank Sum Test Question 1: Alzheimer Drug A randomized double-blind test was done to test the effectiveness of a drug

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Wmw Rank Sum Test Question 1 Alzheimer Drug A Randomized Double Blind Test Was Done To Test The Effectiveness Of A Drug 1 (79.33 KiB) Viewed 52 times

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WMW Rank Sum Test Question 1: Alzheimer Drug A randomized double-blind test was done to test the effectiveness of a drug designed to improve memory in Alzheimer's patients. 4 patients took the drug and 3 took the placebo. Patients were given a pre and post memory test (a list of 20 words and asked to recall them). The numbers below are the (post test score - pre test score) for each person. A positive score shows an improvement. Drug Group: 9, 10, 5, 3 Placebo group: 3, -2, -1 a. What is the Rank sum for the Drug Group? 21.50 Computer's answer now shown above. You are correct. Previous Tries Your receipt no. is 159-7339 ? b. What is the Rank sum for the Placebo Group? 6.50 Computer's answer now shown above. You are correct. Previous Tries Your receipt no. is 159-5221 ?
Question 1 again, this time using U statistic instead of Rank Sum Drug Group: 9, 10, 5, 3 Placebo group: 3, -2, -1 a. What is the U statistic for the Drug Group? (Count the number of times the Drug group scores surpass Placebo group scores) Udrug -5 Submit Answer Incorrect. Tries 1/3 Previous Tries b. What is the U statistic for the Placebo Group? Uplacebo = Submit Answer Tries 0/3 c. Let n₁ be the number of patients in the Drug group and n₂ be the number of patients in the Placebo group. The general formula for the total sum of the U statistics of these two group is (n+n²-1)/2 ոլ Ոշ O [(n1 + n2)2 - 1]/4 Submit Answer Tries 0/1 d. If the null were true and the drug worked no better than the placebo, would the expected value for the U of the 2 groups be the same? Incorrect No, because there's chance variation. Correct: Yes. Incorrect No, because they have different sample sizes. Computer's answer now shown above. Incorrect. Tries 1/1 Previous Tries e. Fill out the Chart below:
f. Since the sample sizes are small, what test-statistic can we use? O we can still use the Z-stat since this is a non-parametric test O the exact probability distribution of U under the null provided by U tables (using the smaller U) t-statistics Submit Answer Tries 0/2 g. Even though the sample sizes are not ≥7 go ahead and use the Normal Approximation to test Ho: The drug works no better than the placebo in the population HA: The drug does work better than the placebo in the population for some segments of the population. Compute |Z| and the p-value, assuming SER= (same for either group) Absolute value of Z, IZI = Submit Answer Tries 0/3 Find the p-value using this calculator: nin₂(N+1). 12