Concept explainers
Triglycerides and Gender Using the NHANES data, we performed an ANOVA to test whether gender is associated with level of triglycerides, a form of fat, in the blood. ANOVA and t-test output from a two-sample t-test is shown. In both cases, we are testing the hypothesis that the mean triglyceride levels for men and women are different. Assume that conditions for both tests have been met.
Compare the output by comparing p-values. Square the t-value to see what you get for comparison. Explain.
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INTRODUCTORY STATISTICS (LOOSELEAF)
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- Ankle Brachial Index. The ankle brachial index (ABI) compares the blood pressure of a patient’s arm to the blood pressure of the patient’s leg. The ABI can be an indicator of different diseases, including arterial diseases. A healthy (or normal) ABI is 0.9 or greater. In a study by M. McDermott et al. titled “Sex Differences in Peripheral Arterial Disease: Leg Symptoms and Physical Functioning” (Journal of the American Geriatrics Society, Vol. 51, No. 2, pp. 222–228), the researchers obtained the ABI of 187 women with peripheral arterial disease. The results were a mean ABI of 0.64 with a standard deviation of 0.15. At the 1% significance level, do the data provide sufficient evidence to conclude that, on average, women with peripheral arterial disease have an unhealthy ABI?arrow_forwardAs an occupational health epidemiologist you are required to measure the effect of stress on the workers in your manufacturing plant. Two different tests previously developed to measure stress in industrial workers are selected: stress test alpha and stress test delta. The sensitivity and specificity of each test are shown below. Which test generates the greatest proportion of false negatives? Stress Test Alpha Stress Test Delta Sensitivity = 60% 75% M Specificity = 95% 90% Stress Test Alpha Stress Test Deltaarrow_forwardA test was conducted of two overnight mail delivery services. Two samples of identical deliveries were set up so that both delivery services were notified of the need for a delivery at the same time. The hours required to make each delivery follow. Do the data shown suggest a difference in the delivery times for the two services? Use a .05 le of significance for the test. Use Table 1 of Appendix B. Click on the datafile logo to reference the data. DATA file Service Delivery 1 2 24.5 26.0 28.0 21.0 18.0 36.0 25.0 21.0 24.0 26.0 31.0 28.0 25.5 32.0 20.0 19.5 28.0 29.0 22.0 23.5 29.5 30.0 3 4 6. 9. 10 11 What is the z-statistic? If required, round your answer to two decimal places. Enter negative values as negative number, if necessary. .30 What is the p-value? If required, round your answer to two decimal places. .7642 Conclude:arrow_forward
- A researcher hypothesizes that different colors of cars result in different average speeds. To test this claim, she took a random sample of 20 people who own 4 different colors of colors of cars (n = 20, N = 80, G = 4), and she then tracks their average speed on the highway for a week of driving. The following ANOVA table has some of her results. Please help her answer her research questions by completing the following ANOVA table below and answering the follow-up questions. Be sure to label your answers with the appropriate letter and show all your work! Source Sums of Squares df Mean Square F Effect (between) Error (within) 100.90 ------ Total 170.10 ------- ------ a) What is the Sums of Squares (SS) between (effect)? b) What are the Mean Square (MS) between (effect) and the MS within (error)? c) What are the degrees of freedom (df) between, the df within, and the df total? d) What is the overall F-statistic? e) Based on the…arrow_forwardA test was conducted of two overnight mail delivery services. Two samples of identical deliveries were set up so that both delivery services were notified of the need for a delivery at the same time. The hours required to make each delivery follow. Do the data shown suggest a difference in the delivery times for the two services? Use a .05 level of significance for the test. Use Table 1 of Appendix B. Click on the datafile logo to reference the data. DATA file Service Delivery 1 2 24.5 26.0 28.0 21.0 18.0 36.0 25.0 21.0 24.0 26.0 31.0 28.0 25.5 32.0 20.0 19.5 28.0 29.0 22.0 23.5 29.5 30.0 What is the z-statistic? If required, round your answer to two decimal places. Enter negative values as negative number, if necessary. -.31 What is the p-value? If required, round your answer to two decimal places. .76 Conclude. 12345 7890:=arrow_forwardWe will be using stress dataset to compare the stress level of college students and the general population. Stress level score is based on three metrics, 1. Responsiveness, 2. Exertion Balance, and 3. Sleep patterns. The scale is from 0 to 30, the lower the score the less stress. Use ANOVA to answer the following questions: Question Generate a boxplot of stress score by the group using proc boxplot in SAS. Describe your observations. Compare the means and variances of stress score by group. Explain if any of the assumptions of ANOVA is violated. Write out the ANOVA model. Assuming you want to compare the stress level of college students and the general population, write out the null and the alternative hypotheses. Fit a one-way ANOVA to compare the stress score for the college students and the general population. Using the result in question 5, test the hypothesis and make a statistical decision. What further statistical analysis might you perform if the null hypothesis is rejected.arrow_forward
- A study examined the link between sodium intake and blood pressure inchildren and adolescents between the ages of 8 and 18. The mean systolicblood pressure (SBP) was 112.8 mm Hg among the 636 study participants whowere overweight or obese and consumed high levels of sodium. Based on thisdata the researchers need to decide if they believe that the mean systolicblood pressure for the group was higher than for other groups. a. What would be a Type I error in this context? Your answer shouldconsist of both the researchers’ decision and what the reality is. b. What would be a Type II error in this context? Your answer shouldconsist of both the researchers’ decision and what the reality is.arrow_forwardplease do the full problem!arrow_forwardHow is my work? Should anything be changed? A researcher wanted to examine the effect of a new math study skills program on second graders. Fifteen students took the new study skills program for six weeks and then took a standardized math exam, which is known to have a population mean score of µ = 80. The scores on the exam for the 15 students (who took the study skills program) are reported below. Scores on the standardized math exam for the 15 students:78, 85, 83, 75, 81, 85, 84, 82, 78, 83, 78, 90, 85, 83, 81 Test to see whether the students who took the new study skills program have significantly higher test scores than the national average. Perform the appropriate test in SPSS using α = .05 a. State the null and alternative hypotheses below. Null hypothesis: H0: μ = 80. Alternative hypothesis: H1: μ > 80 b. What type of test should be run on the data (be specific with the exact name of the test)? For example, don’t just state “t test,” but the specific t-test used. One sample…arrow_forward
- Social functioning is the ability for an individual to interact or adapt in a normal or usual way in social environments. Albert et al. (2007) asked if relatives of patients with OCD are as healthy as those in general healthy populations. They measured the social functioning of relatives using a 36-item survey with scores ranging from 0 (worst possible health) to 100 (best possible health). The mean score for the general healthy population was 77.43. Using the sample data, test whether there was a difference. Scores: 20, 60, 48, 92, 50, 82, 48, 90, 30, 68, 43, 54, 60, 62, 94, 67, 63, 85 State hypotheses 2. Set the criteria using α= 0.05 3. Calculate t 4. What should you conclude?arrow_forwardWhen nicotine is absorbed by the body, cotinine is produced. A measurement of cotinine is therefore a good indicator of how much a person smokes. In the table below are the number of cigarettes smoked per day and the subjects’ cotinine level (ng/mL). Use a significance level of 0.05 and Spearman’s Rank correlation to determine if there is an association between the number of cigarettes smoked and the subjects’ cotinine level. State the null and alternative hypothesis Calculate the test statistic The critical value, and your decision and conclusion. Cigarettes (per day) 60 10 4 15 10 1 20 8 7 10 10 20 Cotinine 179 283 75.6 174 209 9.51 350 1.85 43.4 25.1 408 344arrow_forward
- Glencoe Algebra 1, Student Edition, 9780079039897...AlgebraISBN:9780079039897Author:CarterPublisher:McGraw HillBig Ideas Math A Bridge To Success Algebra 1: Stu...AlgebraISBN:9781680331141Author:HOUGHTON MIFFLIN HARCOURTPublisher:Houghton Mifflin Harcourt