## MS Mod 15 Logistic regression probability of success practice exam...

 Author Message NEAS Supreme Being         Group: Administrators Posts: 4.2K, Visits: 1.2K MS Module 15 Logistic regression probability of success practice exam questions(The attached PDF file has better formatting.)A statistician uses a logistic regression model:●    The independent variable X is a quantitative predictor.●    The dependent variable Y is 1 if the observation is a success and 0 otherwise. The estimate of β1 is -0.21The odds of success at X = 1.8 are 0.4493Question 15.1: Probability of successWhat is the probability of success at X = 1.8?Answer 15.1: 0.4493 / (1 + 0.4493) = 31.00%(probability = odds ratio / (1 + odds ratio)Question 15.2: Multiplicative change in the odds ratioWhat is the multiplicative change in the odds ratio when x increases by 1 unit?Answer 15.2: e-0.21 = 0.8106(the multiplicative change in the odds ratio when x increases by 1 unit = exp(β1)Question 15.3: Odds of success What are the odds of success at X = 2.7?Answer 15.3: 0.4493 × 0.8106(2.7 – 1.8) = 0.3719(odds ratio at point X3 = odds ratio at point X2 × (multiplicative change in odds ratio)(value of point X3 – value of point X2) Question 15.4: Probability of successWhat is the probability of success at X = 2.7?Answer 15.4: 0.3719 / (1 + 0.3719) = 27.11%(probability = odds ratio / (1 + odds ratio)Question 15.5: Odds of success What are the odds of success at X = 0?Answer 15.5: 0.4493 × 0.8106(0 – 1.8) = 0.6557(odds ratio at point X3 = odds ratio at point X2 × (multiplicative change in odds ratio)(value of point X3 – value of point X2) Question 15.6: Probability of successWhat is the probability of success at X = 0?Answer 15.6: 0.6557 / (1 + 0.6557) = 39.60%(probability = odds ratio / (1 + odds ratio)Question 15.7: β0What is β0?Answer 15.7: ln(0.6557) = -0.4221(β0 = ln(odd ratio at X = 0) ) Attachments MS Module 15 Logistic regression probability of success practice exam questions.pdf (225 views, 38.00 KB)
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