Question 1193130: Samantha is about to take a final exam that consists of 20 questions. To motivate her to study, her parents promised her $1500 if she gets at least 16 questions right. The questions are multiple choice and the probability of her getting a question right is 0.85 on each question of the final exam.
a) What is the probability that she gets exactly 16 questions right?
b) What is the probability that she gets at least 16 questions right?
c) What is the expected value of reward in dollars for her on this exam?
Show steps, list all numbers the calculator gives in the answer, and do not round answers.
Answer by Boreal(15235)   (Show Source):
You can put this solution on YOUR website! a, it is 20C16*0.85^16*0.15^4=0.1821
b. At least 16 is 16-20 with probability 0.8298 2d VARS to 1-binomcdf(20,0.85,15); the 1- means we want the right side of the distribution up to 15.
c. $1500*0.8298=$1244.77
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