Question: Here is a simple probability model for multiple-choice tests. Suppose that each student has probability p of correctly answering a question chosen at random from a universe of possible questions. (A strong student has a higher p than a weak student.) Answers to different questions are independent. Jodi is a good student for whom p = 0.75.
If the test contains 250 questions, what is the probability that Jodi will score 77% or lower?
D. 0.2148 Edit
x=77% of 250=192.5
Need to find P(x<=192.5)=?
test statistic, z= (x- np)/sqrt(np(1-p))=(192.5-187.5)/sqrt(187.5*0.25)=0.73
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