Out of all the red heads how many are boys give answer as a fraction
2 answers:
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Answer:
a) p=0.2
b) probability of passing is 0.01696
.
c) The expected value of correct questions is 1.2
Step-by-step explanation:
a) Since each question has 5 options, all of them equally likely, and only one correct answer, then the probability of having a correct answer is 1/5 = 0.2.
b) Let X be the number of correct answers. We will model this situation by considering X as a binomial random variable with a success probability of p=0.2 and having n=6 samples. We have the following for k=0,1,2,3,4,5,6
.
Recall that In this case, the student passes if X is at least four correct questions, then
c)The expected value of a binomial random variable with parameters n and p is . IN our case, n=6 and p =0.2. Then the expected value of correct answers is