# DAT 520 Problem Set 3.docx - DAT 520 Problem Set 3...

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DAT 520 Problem Set 3 Cumulative and Conditional Probability Problem 1: You are taking a 10 question multiple choice test. If each question has four choices and you guess on each question, what is the probability of getting one question correct? [Hint: This is a binomial in the form of 10 choose 1 with p=.25.]
Problem 2: What is the probability of getting seven questions correct? [Hint: This is a binomial as Q1 with modified choose value.]
Problem 3: What are your chances of answering seven questions correctly if you can reliably eliminate one possible answer from each question? [Hint: This is a binomial as Q2 with a modified p value.]
Problem 4: Let’s say, instead, that the test is an adaptive test; you get to answer more questions based on your previous success. This test is structured like this: First you have to answer three questions and if you are correct on two of them, you get to answer three more questions.