Probability (1 Viewer)

[cutemouse]

Could someone please do the following question?

Thanks


The probability of George being late to class is 0.2. He is supposed to attend 20 classes in a week. The Year Level Coordinator has said that if George is late to three or more classes in a week he will receive a detention.

(i)What is the probability that George receives a detention for being late? Express your answer correct to two decimal places. (2 marks)

(ii) The principal said that if George received n or more detentions for being late in a ten week term, he would be suspended. George’s mates worked out that the probability of George being suspended was 0.65 (correct to two decimal places).
Using your answer to part (i), find the value of n. (2 marks)

 

[Prashant Sallan]

hey, is the answer to i) 0.86 ? this is how i got it, lol - i think i done something wrong :S, part ii) is the 'nested' probablilty question..

 

[Prashant Sallan]

 

[hermand]

i got 0.01 for the first bit, which means he would have to get 65 detentions, which obviously doesn't make sense if he can only get one a week.

i haven't done probability in two years though, so don't trust anything i say haha.

prashant sallan, it couldn't be 0.86 because if he has only a 0.2 chance of being late, he couldn't have a greater chance to be late three times, cause to be late three times it's 0.2^3, and then 0.2^4 if he's late four times, etc.

 

[cutemouse]

Could anyone else please help confirm these answers? Because I don't have the answers for this question.

Thanks

EDIT: I think I may know why you got your answer wrong.. did you put parenthesis outside your binomial terms?

You should get 1-0.2060...

Anyway, could you tell me how you got that?

Thanks a million

 

[cutemouse]

hey, is the answer to i) 0.86 ? this is how i got it, lol - i think i done something wrong :S, part ii) is the 'nested' probablilty question..

no, the answer is 0.79 (to 2dp)... but your working was correct! How did you get that?

Thanks

 

[Timothy.Siu]

no, the answer is 0.79 (to 2dp)... but your working was correct! How did you get that?

Thanks

he just did 1-(prob that he's late to one+late to two+late to three)