# Multiple choice

#### Jurij

Hey...

I have just taken my first and last multiple choice test ever, because I live in Denmark. I think there is a high chance of me not passing because of my terrible memory, even though I have studied a lot.
But I am having a really hard time calculation the probability, I don't understand all the weird letters in the formula for it.

What is the probability of passing the test if you have to have minimum 60% correct out of 60 questions and every question have 4 possible answers(A,B,C,D).

Maybe there a calculator online where I can just put those numbers in? (Cool)

#### mr fantastic

MHF Hall of Fame
Hey...

I have just taken my first and last multiple choice test ever, because I live in Denmark. I think there is a high chance of me not passing because of my terrible memory, even though I have studied a lot.
But I am having a really hard time calculation the probability, I don't understand all the weird letters in the formula for it.

What is the probability of passing the test if you have to have minimum 60% correct out of 60 questions and every question have 4 possible answers(A,B,C,D).

Maybe there a calculator online where I can just put those numbers in? (Cool)
I assume you are guessing every answer ....?

Then X ~ Binomial(n = 60, p = 1/4) and you need to calculate Pr(X > 36).

(Note that 60% of 60 = 36)

#### Jurij

As I said before I haven't studied mathematics, so all those letters make no sense to me.

I don't know what Pr, X or ~ means or how to use them.

#### mr fantastic

MHF Hall of Fame
As I said before I haven't studied mathematics, so all those letters make no sense to me.

I don't know what Pr, X or ~ means or how to use them.
If you have guessed every answer then the probability of you getting 60% or better is zero, correct to four decimal places.

#### BertieWheen

Still, it could happen...

For instance one mock chemistry test I guessed every answer without looking at the questions (it was multiple choice, 4 choices for each question, 36 questions) as a matter of sheer curiosity and I got 77.8% correct (Giggle)

That's the only test I've ever guessed btw.

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