3. Suppose a particular test for whether someone has been using cannabis is 91% sensitive,meaning the true positive rate 0.91. Therefore it leads to 91% true positive results (correctidentification of drug use) for cannabis users and 9% false negatives. The test is also 82%specific, meaning the true negative rate 0.82. Therefore the test correctly identifies 82% ofnon-users as non-users, but also generates 18% false positives. Assuming 0.04 prevalence(frequency), meaning 4% of people in the general population use cannabis, what is theprobability that a random person who tests positive is really a cannabis user?

Given Information: The true positive rate is 0.91 False-negative is 0.09 The true negative rate is…

Answered: 3. Suppose a particular test for…

MATLAB: An Introduction with Applications

6th Edition

ISBN:9781119256830

Author:Amos Gilat

Publisher:Amos Gilat

Chapter1: Starting With Matlab

Section: Chapter Questions

Problem 1P

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A professor believes that, for the introductory art history classes at his university, the mean test score of students in the evening classes is lower than the mean test score of students in the morning classes. He collects data from a random sample of 250 students in evening classes and finds that they have a mean test score of 76.8. He knows the population standard deviation for the evening classes to be 7.2 points. A random sample of 200 students from morning classes results in a mean test score of 77.8. He knows the population standard deviation for the morning classes to be 1.9 points. Test his claim with a 90% level of confidence. Let students in the evening classes be Population 1 and let students in the morning classes be Population 2. Step 1 of 3 : State the null and alternative hypotheses for the test. Fill in the blank below. H0: μ1=μ2 Ha: μ1__μ2
A researcher speculates that because of differences in diet, Japanese children have a lower mean blood cholesterol level than U.S. children do. Suppose that the mean level for U.S. children is known to be 175. Let ? represent the true mean blood cholesterol level for Japanese children. What hypotheses should the researcher test? H0: ? = 175 versus Ha: ? > 165H0: ? = 175 versus Ha: ? < 185 H0: ? = 175 versus Ha: ? < 175H0: ? = 175 versus Ha: ? > 175H0: ? = 185 versus Ha: ? > 175
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In Professor Friedman's economics course the correlation between the students' total scores prior to the final examination and their final-examination scores is r = 0.5. The pre-exam totals for all students in the course have mean 275 and standard deviation 38. The final-exam scores have mean 75 and standard deviation 6. Professor Friedman has lost Julie's final exam but knows that her total before the exam was 290. He decides to predict her final-exam score from her pre-exam total. (a) What is the slope of the least-squares regression line of final-exam scores on pre-exam total scores in this course? (Round your answer to four decimal places.) What is the intercept? (Round your answer to two decimal places.) (b) Use the regression line to predict Julie's final-exam score. (Round your answer to one decimal place.) -2 (c) Julie doesn't think this method accurately predicts how well she did on the final exam. Use r² to argue that her actual score could have been much higher (or much…
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Mark performed a two-sample z-test for proportions to test the hypothesis that there was no difference in the proportion who support increasing student fees between male and female students at a particular university. Mark obtained a z-statistic of 0. Based on this information, which of the following is always true. The sample proportions for male and females will be the same as the hypothesized proportions for male and female students at this university. The sample proportions for both male and female students at this university will be 0. All male and female students in the sample will feel the same way about supporting the increase in student fees. The sample proportions will be the same for both male and female students at this university. Test whether p1>p2 The sample data are x1=116,n1=258,x2=135,n2=311. Conduct a test at the α=0.10 level of significance. Determine the correct null and alternative hypothesis below. Determine the test statistic. Find the P-value: What is…
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