Wilcoxon Rank-Sum Test. In Exercises 5–8, use the Wilcoxon rank-sum test.
8. Blanking Out on Tests In a study of students blanking out on tests, the arrangement of test items was studied for its effect on anxiety. The following scores are measures of “debilitating test anxiety” (based on data from “Item Arrangement, Cognitive Entry Characteristics, Sex and Test Anxiety as Predictors of Achievement in Examination Performance,” by Klimko, Journal of Experimental Education, Vol. 52, No. 4.) Is there sufficient evidence to support the claim that the two samples are from populations with different
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Elementary Statistics (13th Edition)
- please solve this problem step by step and make it quick pleasearrow_forwardplease solve this problem step by step and make it quick pleasearrow_forward8.67 Free recall memory strategy. Psychologists who study ①memory often use a measure of "free recall" (e.g., the RECALL number of correctly recalled items in a list of to-be- remembered items). The strategy used to memorize the list-for example, category clustering-is often just as important. Researchers at Central Michigan University developed an algorithm for computing measures of cat- egory clustering in Advances in Cognitive Psychology (Oct. 2012). One measure, called ratio of repetition, was recorded for a sample of 8 participants in a memory study. These ratios are listed in the table. Test the theory that the average ratio of repetition for all participants in a similar memory study differs from .5. Select an appropriate Type I error rate for your test. .25 .43 .57 .38 .38 .60 .47 .30 Source: Senkova, O., & Otani, H. "Category clustering calculator for free recall." Advances in Cognitive Psychology, Vol. 8, No. 4, Oct. 2012 (Table 3).arrow_forward
- 8.64 Radon exposure in Egyptian tombs. Refer to the D Radiation Protection Dosimetry (Dec. 2010) study TOMBS of radon exposure in Egyptian tombs, Exercise 7.39 (p. 334). The radon levels-measured in becquerels per cubic meter (Bq/m³)-in the inner chambers of a sam- ple of 12 tombs are listed in the table. For the safety of the guards and visitors, the Egypt Tourism Authority (ETA) will temporarily close the tombs if the true mean level of radon exposure in the tombs rises to 6,000 Bq/m³. Consequently, the ETA wants to conduct a test to deter- mine if the true mean level of radon exposure in the tombs is less than 6,000 Bq/m³, using a Type I error probabil- ity of .10. A SAS analysis of the data is shown on p. 399. Specify all the elements of the test: Ho, Ha, test statistic, p-value, a, and your conclusion. 50 390 910 12100 180 580 7800 4000 3400 1300 11900 1100 N Mean Std Dev Std Err Minimum Maximum 12 3642.5 4486.9 1295.3 50.0000 12100.0arrow_forwardHow does probability help businesses make informed decisions under uncertainty? Provide an example of how businesses use probability in marketing to predict customer behavior. Why is probability considered essential in financial decision-making, particularly in portfolio management? Discuss how the use of probability in inventory management can improve customer satisfaction. Compare the role of probability in marketing and financial decision-making. How do the applications differ in their objectives?arrow_forward55 5.5 A glass bottle manufacturing company has recorded data on the average number of defects per 10,000 bottles due to stones (small pieces of rock embedded in the bottle wall) and the number of weeks since the last furnace overhaul. The data are shown below. Defects per 10,000 Weeks 13.0 4 16.1 5 14.5 6 17.8 7 22.0 8 27.4 9 16.8 10 65.6 ☐☐ Defects per 10,000 Weeks 34.2 11 12 49.2 13 66.2 81.2 87.4 14 15 16 114.5 17 a. Fit a straight-line regression model to the data and perform the standard tests for model adequacy. b. Suggest an appropriate transformation to eliminate the problems encoun- tered in part a. Fit the transformed model and check for adequacy.arrow_forward
- One estimate of the proportion of children with autism in the United States is 1 in 100 (Source: http://www.cbsnews.com/stories/2009/10/05/health/main5363192.shtml). Suppose you are interested in the rate of autism among current school-aged children in Utah. You collect a sample of 400 children between the ages of 5 and 18 and find that three have had a previous diagnosis of an autism disorder. You plan to calculate a 95% confidence interval estimator of the proportion of school-aged children in Utah who have ever had a diagnosis of an autism disorder. Which of the following is the most likely reason you would use a Wilson estimator to calculate the confidence interval estimator? It is uncomfortable to define having been diagnosed with autism as a success. It is possible that if even the actual proportion in Utah is 1%, your sample may only have very few children who have had a previous diagnosis of an autism disorder. It is an easier way to calculate the confidence…arrow_forwardProblem 2-6. Need help on why its 1.22arrow_forwardScenario: As a data analyst for a retail company, you are tasked with examining the relationship between televisions screen size, and prices. Your analysis will involve both correlation and regression methods to quantify and interpret this relationship Make a Scatterplot of screen size vs. price. Explain in one sentence, does there appear to be a positive or a negative correlation between price and screen size? Paste a snapshot of the plot here. Please do not copy paste. Question 1: What is the value of correlation coefficient between screen size and price? Discuss the direction of the relationship (positive, negative, or zero relationship). Also discuss the strength of the relationship Estimate the relationship between screen size and price using a simple linear regression model and interpret the estimated coefficients. In your interpretation, tell the dollar amount by which price will change for each unit of increase in screen size. (The answer for the second part of this…arrow_forward
- very time you conduct a hypothesis test, there are four possible outcomes of your decision to reject or not reject the null hypothesis: (1) You don’t reject the null hypothesis when it is true, (2) you reject the null hypothesis when it is true, (3) you don’t reject the null hypothesis when it is false, and (4) you reject the null hypothesis when it is false. Consider the following analogy: You are an airport security screener. For every passenger who passes through your security checkpoint, you must decide whether to select the passenger for further screening based on your assessment of whether he or she is carrying a weapon. Suppose your null hypothesis is that the passenger has a weapon. As in hypothesis testing, there are four possible outcomes of your decision: (1) You select the passenger for further inspection when the passenger has a weapon, (2) you allow the passenger to board her flight when the passenger has a weapon, (3) you select the passenger for further inspection when…arrow_forwardEKS C ALEKS - Kim Johnson - Ch 6S × 4 www-awy.aleks.com alekscgi/x/sl.exe/16_u-lgNs/kr7j8FB)--BjuvZG weRMign 4tCy83MpSgONH0-ovaPm-Zym e Chrome isn't your default browser Set as default Ch 6 Sec 4 Homework Question 4 of 4 (1 point) | Question Attempt: 2 of Unlimited ✓ 2 ✓ 3 = 4 Stress at work: In a poll conducted by the General Social Survey, 81% of respondents said that their jobs were sometimes or always stressful. Two hundred workers are chosen at random. Use the TI-84 Plus calculator as needed. Round your answer to at least four decimal places. (a) Approximate the probability that 155 or fewer workers find their jobs stressful. (b) Approximate the probability that more than 145 workers find their jobs stressful. (c) Approximate the probability that the number of workers who find their jobs stressful is between 154 and 172 inclusive. Part 1 of 3 The probability that 155 or fewer workers find their jobs stressful is 0.1207 Part 2 of 3 bility that more than 145 workers find their jobs…arrow_forwardA case-control (or retrospective) study was conducted to investigate a relationship between the colors of helmets worn by motorcycle drivers and whether they are injured or killed in a crash. Results are given in the accompanying table. Using a 0.01 significance level, test the claim that injuries are independent of helmet color. Color of Helmet Black White Yellow Red Blue Controls (not injured) 499 373 32 159 79 Cases (injured 221 108 8 66 38 or killed) Click here to view the chi-square distribution table. Chi-square distribution table Area to the Right of the Critical Value Degrees of Freedom 0.995 0.99 0.975 0.95 0.90 0.10 0.05 0.025 0.01 0.005 C. Ho: Injuries and neimet color are dependent H₁: Injuries and helmet color are independent D. Ho: Whether a crash occurs and helmet color are dependent 1 0.001 0.004 0.016 2.706 3.841 5.024 6.635 7.879 2 0.010 0.020 0.051 0.103 0.211 4.605 5.991 7.378 9.210 10.597 3 0.072 0.115 0.216 0.352 0.584 6.251 7.815 9.348 11.345 12.838 4 0.207 0.297…arrow_forward
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