# Intro Stats Problem.

#### stats151

##### New Member
A student takes a true or false test with 15 questions. He guesses on every question.

1) Find the probability that he gets atleast 1 question right
2) Find the probability he gets 60% or higher.

I am stuck. I know it is something with perms and coms. Any help would be great.

#### Dason

Do you know about the binomial distribution?

#### stats151

##### New Member
No, it isn't in the chapter of this textbook, so I'm assuming its not used. Im just trying to read the textbook examples and try to figure it out but I can seem to get any answer that makes sense.

#### Dason

Well the binomial distribution makes things easier it looks like this question is basically asking you to derive and use the binomial distribution which is entirely possible based on first principles.

Hint for question 1: Can you figure out the probability that they get 0 correct is?

#### stats151

##### New Member
Okay so I'm doing 15 choose 15. Then 2^15. So he has a 1/32768 chance of getting 0 right.

#### stats151

##### New Member
I was wrong binomial distribution is in the chapter its just further into it.

#### stats151

##### New Member
but its not at the part where the question so i feel like you aren't suppose to use it.