# A level maths binomial distribution question

https://imgur.com/a/owz3LsN

part a to this question i thought it’s simple make the distribution X~B( 1,0.25) and then do (X=0) to work out if there’s no faults but no?…
Original post by esha06
https://imgur.com/a/owz3LsN
part a to this question i thought it’s simple make the distribution X~B( 1,0.25) and then do (X=0) to work out if there’s no faults but no?…

Looks like they expected you to use a poisson rather than binomial. Its a poisson because there could be 3 signal failures say in 1 day, whereas a binomial assumes that the max number of signal failures is 1 as thats the number of days.
(edited 1 month ago)
Original post by mqb2766
Looks like they expected you to use a poisson rather than binomial. Its a poisson because there could be 3 signal failures say in 1 day, whereas a binomial assumes that the max number of signal failures is 1 as thats the number of days.

omg i was thinking that but i literally don’t ever remember us doing poisson distribution in school 💀 i’m so done for this exam
Original post by esha06
omg i was thinking that but i literally don’t ever remember us doing poisson distribution in school 💀 i’m so done for this exam

i dont think poisson is on the a level maths spec . maybe further maths?
Original post by carbon1k
i dont think poisson is on the a level maths spec . maybe further maths?
oh thank god, i was thinking that but my teacher put it on a worksheet he made for binomial maybe he didn’t realise it was poisson
(edited 1 month ago)