# How to estimate the probability of a certain number of students with cohorts using R?

I'm trying to calculate the probability of this task. In a class a teacher marks for every 9 exam scripts, he makes up a grade for the tenth student, not reading it at all. The external examiner checks a random sample of exams equal to the rounded up square root of the number of people on the module. The examiner will identify an unmarked exam correctly 94% of the time, and will identify a marked exam as unmarked 0% of the time. Write a program that will estimate the probability of the teacher getting caught given a certain number of students. Test it with cohorts of 40, 80 and 160.

`#This is my code: n = 10 x = 160 ntrials = 1000 trials = rep(0,ntrials) for (j in 1:ntrials) { y = sample(x,n) } mean(trials)`

How should I calculate the probability! Kindly help me. TIA

Hi, welcome!

Please have a look to our homework policy, homework inspired questions are welcome but they should not include verbatim instructions from your course.

I suggest you try to solve this without R first.