Wilcoxon Rank-Sum Test. In Exercises 5–8, use the Wilcoxon rank-sum test.
7. Clinical Trials of Lipitor The sample data below are changes in LDL cholesterol levels in clinical trials of Lipitor (atorvastatin). It was claimed that Lipitor had an effect on LDL cholesterol. (The data are based on results given in a Parke-Davis memo from David G. Orloff, M.D., the medical team leader for clinical trials of Lipitor. Pfizer declined to provide the author with the original data values.) Negative values represent decreases in LDL cholesterol. Use a 0.05 significance level to test the claim that for those treated with 20 mg of Lipitor and those treated with 80 mg of Lipitor, changes in LDL cholesterol have the same
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Elementary Statistics (13th Edition)
- Are you an impulse shopper? A survey of 1000 grocery shoppers indicated that 24% of males and 57%of females make an impulse purchase every time they shop. Assume that the survey consisted of 500 males and 500 females. Complete parts (a) and (b) below. Question content area bottom Part 1 a. At the 0.01 level of significance, is there evidence of a difference in the proportion of males and females who make an impulse purchase every time they shop? Let group 1 be the males, and let group 2 be the females. State the null and alternative hypotheses. Choose the correct answer below. A. H0:π1≥π2 H1:π1<π2 BH0:π1≠π2 H1:π1=π2 C.H0:π1≤π2 H1:π1>π2 D.H0:π1=π2 H1:π1≠π2 E.H0:π1<π2 H1:π1≥π2 F.H0:π1>π2 H1:π1≤π2 Part 2 Calculate the test statistic. χ2STAT= (Round to three decimal places as needed.) Part 3 Determine the critical value. The critical value is - (Round to three decimal places as needed.) Part 4 State…arrow_forwardStatistics students in Oxnard College sampled 11 textbooks in the Condor bookstore, and recorded the number of pages in each textbook and its cost. The bivariate data is shown below, Number of Pages (x) Cost(y) 962 93.96 246 25.68 803 62.24 907 80.56 640 68.2 944 77.52 847 78.76 919 71.52 591 59.28 393 47.44 476 42.08 A student calculates a linear model (Please show your answers to two decimal places) Use the model above to estimate the cost when number of pages is 955 Cost - $ (Please show your answer to 2 decimal places.) Submit Question F5 F6 F7 F8 F9 F3arrow_forwardage As a labor economist, you would like to measure the effect that an older sibling has on the average level of education for the youngest sibling. You randomly select 137 individuals from t Longitudinal Study of Youth (NLSY) that have an older brother (population 1) and 245 individuals that have an older sister (population 2) and compare the average level of education of the sibling depending on having an older brother or older sister. Which of the following is the best test to use for your hypothesis assuming only the following tests are available? Use "Formula Sheet Fall 2020" if necessary. Select one: O a. A paired sample t-test for the difference in two population means O O O b. Az-test for the difference in two population means c. A t-test for the difference in two population means with unknown but equal variances d. A chi square test for single population variance e. An F-test for the ratio of two population variances Finisharrow_forward
- Statistics students in Oxnard College sampled 11 textbooks in the Condor bookstore and recorded the number of pages in each textbook and its cost. The bivariate data are shown below: Number of Pages (x) Cost(y) 968 72.4 317 40.85 210 33.5 470 45.5 403 41.15 517 35.85 556 50.8 725 50.25 410 43.5 805 60.25 487 45.35 A student calculates a linear model y = (Please show your answers to two decimal places) %3D Use the model to estimate the cost when number of pages is 890. Cost = $ (Please show your answer to 2 decimal places.) %3Darrow_forwarded weight (in kg) and total serum cholesterol (TSC in mg/dl) data for five men (n = 5). They tested for association between weight and TSC at 5% level of significance. weight, X TSC, Y X*X Y*Y X*Y 37 2.9 1369 8.41 107.3 50 0.7 2500 0.49 35.0 67 3.3 4489 10.89 221.1 70 4.2 4900 17.64 294.0 57 3.8 3249 14.44 216.6 SUM: 281 14.9 16507 51.87 874.0 What are the Null and Alternate hypotheses for this test? Clearly label your answers as HỌ or H1. (Do not use a numerical format. Both of your statements must be in sentence form, and say something about the weightarrow_forwardCan a low barometer reading be used to predict maximum wind speed of an approaching tropical cyclone? For a random sample of tropical cyclones, let x be the lowest pressure (in millibars) as a cyclone approaches, and let y be the maximum wind speed (in miles per hour) of the cyclone. 1004 975 992 935 985 922 40 100 65 145 84 151 A USE SALT (a) Make a scatter diagram of the data and visualize the line you think best fits the data. 1000 1000 980 980 960 960 940 940 920E 920 40 60 80 100 120 140 40 60 80 100 120 140 x (lowest pressure (in millibars)) x (lowest pressure (in millibars)) 140 140 120 120 100 100 80 80 60 60 40 1000 960 980 940 40 1000 960 980 940 x (lowest pressure (in millibars)) x (lowest pressure (in millibars)) y (maximum wind speed (in miles per hour) y (maximum wind speed (in miles per hour)) y (maximum wind speed (in miles per hour)) y (maximum wind speed (in miles per hour) ..arrow_forward
- Aspirin III: Decision and Conclusion Regarding the experiment in the data frame Aspirin from the abd package, the researchers wanted to know whether or not taking aspirin affects one's risk of developing cancer. Recall that they defined their parameters as follows: p1 = the proportion of ALL individuals who would develop cancer, if all of them were to take aspirin like the subjects in the Aspirin group did. p2 = the proportion of ALL individuals who would develop cancer, if all of them were to take a placebo, like the subjects in the placebo group did. They ran the code for a two-sided significance test and got the following results: ## ## ## Inferential Procedures for the Difference of Two Proportions p1-p2:## cancer grouped by treatment ## ## ## Descriptive Results:## ## yes n estimated.prop## Aspirin 1438 19934 0.07214## Placebo 1427 19942 0.07156## ## ## Inferential Results:## ## Estimate of p1-p2: 0.0005805 ## SE(p1.hat - p2.hat): 0.002586 ## ##…arrow_forwardAspirin II: Safety Considerations Regarding the experiment in the data frame Aspirin from the abd package, the researchers wanted to know whether or not taking aspirin affects one's risk of developing cancer. Recall that they defined their parameters as follows: p1 = the proportion of ALL individuals who would develop cancer, if all of them were to take aspirin like the subjects in the Aspirin group did. p2 = the proportion of ALL individuals who would develop cancer, if all of them were to take a placebo, like the subjects in the placebo group did. They ran the code for a two-sided significance test and got the following results: ## ## ## Inferential Procedures for the Difference of Two Proportions p1-p2:## cancer grouped by treatment ## ## ## Descriptive Results:## ## yes n estimated.prop## Aspirin 1438 19934 0.07214## Placebo 1427 19942 0.07156## ## ## Inferential Results:## ## Estimate of p1-p2: 0.0005805 ## SE(p1.hat - p2.hat): 0.002586 ## ## 95%…arrow_forwardUsing R Studio to answer the following question:arrow_forward
- Helparrow_forwardFast reactions: In a study of reaction times, the time to respond to a visual stimulus (x) and the time to respond to an auditory stimulus (y) were recorded for each of 7 subjects. Times were measured in thousandths of a second. The results are presented in the following table. Visual Auditory 161 159 176 163 178 201 188 193 201 197 203 206 211 189 Send data to Excel 1895.4286 are known for this data. Use the critical value method to test The least-squares regression line y=b,+b,x= 51.2341+0.7203x and E (x-x) = Ho:B,=0 versus H : B,#0. Can you conclude that visual response is useful in predicting auditory response? Use the a=0.01 level of significance. Part: 0 / 4 System Preferences Part 1 of 4 DEC P ... MacBook Airarrow_forwardLarge Data Sets from Appendix B. In Exercises 25–28, use the data set from Appendix B to test the given claim. Use the P-value method unless your instructor specifies otherwise. Diastolic Blood Pressure for Men Repeat the preceding exercise for adult males instead of adult females.arrow_forward
- Linear Algebra: A Modern IntroductionAlgebraISBN:9781285463247Author:David PoolePublisher:Cengage LearningGlencoe Algebra 1, Student Edition, 9780079039897...AlgebraISBN:9780079039897Author:CarterPublisher:McGraw Hill