Help with a probability question please!!?!?!?

The final test for a stats test is based on 18 different topics and the instructor announces in the class that the exam will have 6 question from six different topics. A student decides to only study 12 topics. What is the probability that from the topics the student studies:

a).No questions are asked?

b).Two questions are asked?

c).All six questions are asked?

Top 2 Answers

A few days ago

Merlyn

Favorite Answer

Let X be the number of question in a topic area the student studied.

X has the binomial distribution with n = 6 trials and success probability p = 12/18 = 2/3

In general, if X has the binomial distribution with n trials and a success probability of p then

P[X = x] = n!/(x!(n-x)!) * p^x * (1-p)^(n-x)

for values of x = 0, 1, 2, …, n

P[X = x] = 0 for any other value of x.

P(X = 0) = 6!/(0! (6 – 0)!) * (2/3) ^ 0 * (1 – 2/3) ^ (6-0)

= 0.001371742

P(X = 2) = 6!/(2! (6 – 2)!) * (2/3) ^ 2 * (1 – 2/3) ^ (6-2)

= 0.082304527

c) P(X = 6) = 6!/(6! (6 – 6)!) * (2/3) ^ 6 * (1 – 2/3) ^ (6-6)

= 0.087791495

A few days ago

norcekri

This is homework *help* — all you’ve done so far is to post the entire problem. Where are you stuck? If it’s simply with the application, think of the 18 topics as colored balls in a bag. Think of the six the student studies as bright red balls; the other twelves are a painfully dull gray. Now can you translate the problem into something like you’ve seen in your textbook? If not, write again and let us know where you’re stuck.

Big favor! Who can do this? please! 10 points!!!! people who actually are nice enough to help!?

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Help with a probability question please!!?!?!?

Help with a probability question please!!?!?!?

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