The tree diagram is correct. P(L|A) means the probability that Susan is late given that she took route A, whereas the question in part (ii) states that the given event is that she is late so |L is used not |A as you suggest. I hope that makes sense.
Thank you for the great videos, it helps a lot! I have a quick question though. I tried to do this exercise and I have done it in the way you did the question in the example (Combining Probabilities > Examples) (2nd question). I am just a bit confused because I can't distinguish questions where you need to rearrange the formula when writing the percentage for conditional probability and where not to. Thanks!
That's hard to answer as it depends on the tree diagram associated with the question. Normally you would only be expected to answer P(AuB) in a Venn diagram.
Thankyou so much for this video! I've started on past exam questions revision and for the whole conditional probability I never quite understood when my teacher explained... but after watching this I feel much more confident and actually understand, esp the P(A/L) not P(L) part. Thankyou once again, this is going to make a huge difference in my end of year exam mark :)
awesome video man, basically we are going to be having a test on conditional probability, but the our school hasn't provided us with text books with questions so that we can revise.... would you mind sending me some question? But once again thanks for the video it really helped me out :-)
Could you please please please do a video on 'Permutations and Combinations'? It's the only topic I have left, then I'm finished w/ my A level studies.
Why do you sometimes use P(L|A)=P(AnL)xP(A) but in this example you used the numbers straight away from the question? Sorry if this is a silly question but im really confused
There's this one thing still confusing me..When finding P(A|L) , The "L" we are considering is 0.085 for the denominator and 0.05 for the numerator ...Why are we using two different Values for L? Shouldn't A intersection L be 0.30*0.085 ?
Thankyou so much mate, my stats teacher goes to mymaths.com and just reads out of the notes :/ its awful. With your help I think I can clock an A; thanks again!! On a side note, Susan goes from going to work to going to school haha :P.
The tree diagram is correct.
P(L|A) means the probability that Susan is late given that she took route A, whereas the question in part (ii) states that the given event is that she is late so |L is used not |A as you suggest.
I hope that makes sense.
Thank you so much, this was one of the few things I was stuck on in S1 but you cleared it up in 8 minutes.
The explaination and qualitybis really good that I didn’t even notice that this vid was posted in 2009…
I enjoy your lectures. You are gifted. Thanks for sharing.
@4xEVERMORE That's ok. I made the question up as a dedication to my wife Susan who is a teacher.
You're welcome
@SparkyChelada Thanks for your comment. Pleased to know you are grasping this tricky topic. It's all in the notation as you said.
I did use Bayes Theorem. The numerator is P(A and L) which is P(A) x P(L|A)
Thank you and I intend to continue putting videos up.
Thank you for the great videos, it helps a lot! I have a quick question though. I tried to do this exercise and I have done it in the way you did the question in the example (Combining Probabilities > Examples) (2nd question). I am just a bit confused because I can't distinguish questions where you need to rearrange the formula when writing the percentage for conditional probability and where not to. Thanks!
That's hard to answer as it depends on the tree diagram associated with the question. Normally you would only be expected to answer P(AuB) in a Venn diagram.
@alfatourist Thank you
Thankyou so much for this video! I've started on past exam questions revision and for the whole conditional probability I never quite understood when my teacher explained... but after watching this I feel much more confident and actually understand, esp the P(A/L) not P(L) part. Thankyou once again, this is going to make a huge difference in my end of year exam mark :)
Susan is going to work at school, she is a teacher. lol
@daphniek1 Cheers
Thank you so much.I have an exam next week and this has helped me 😃
Well explained 🙏
@bollywoodmassive of course
thank you! recommended...!!! easy to understand..clear voice,problem...i get the point..ty!!! keep it up to post more good video...auumm!!!
I always get stuck on questions like these but not anymore !
Thank you so much
العنود محمد I am pleased to hear tat it is now cleared up for you. Well done.
>tat
top kek
Oh thank you soo much! I've been trying to do a question similar to this for the past 1 and half hour...you really helped me out :D
LOL What you studying now
awesome video man, basically we are going to be having a test on conditional probability, but the our school hasn't provided us with text books with questions so that we can revise.... would you mind sending me some question? But once again thanks for the video it really helped me out :-)
For part i, in what cases would we have just simply added the two probabilities i.e 0.05 and 0.90?
Really really cool! Wikipedia was blowing my brains out with jargon
This was really helpful thanks
thank you so much. The video is very helpful!
Could you please please please do a video on 'Permutations and Combinations'?
It's the only topic I have left, then I'm finished w/ my A level studies.
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@redrose11123 Thank you for the complement.
@ExamSolutions is that the Questions in the exams of A,s in january
Why do you sometimes use P(L|A)=P(AnL)xP(A) but in this example you used the numbers straight away from the question? Sorry if this is a silly question but im really confused
really silly question cuz the number were already found so he just plugged them in
There's this one thing still confusing me..When finding P(A|L) , The "L" we are considering is 0.085 for the denominator and 0.05 for the numerator ...Why are we using two different Values for L? Shouldn't A intersection L be 0.30*0.085 ?
Hi exam solution, how would you work out p(AUB) on a tree diagram. thanks
Cool
thanks man!
thank you!!
thanks!
nice lectures
Oh alright I get it, thanks
@franciscojurado0 well done
Waoooh! Thnx for this. You made my day...
@jammy123ism Thanks for sharing
@chocobelge4 Common and irritating mistake
Thankyou so much mate, my stats teacher goes to mymaths.com and just reads out of the notes :/ its awful. With your help I think I can clock an A; thanks again!! On a side note, Susan goes from going to work to going to school haha :P.
What u studying now
hi exam solution, how would you work out p(AUB)
Thank YOu Soo much U saved my 6 marks..~~~
Wouldn't it be P(A|L) on the tree diagram and P(L|A) used in (ii)?
What you studying now
@omar3211 early video
@MEGIDIOT Please read my homepage on my website where it says ActionAid and click on the link.
Nice
why is not true of P(L/A)?
@muhaimen123 Watford, Hertfordshire.
The question is how did you get 70%
I find probability so hard can’t even understand it just can’t
on a tree diagram
But what if she's a teacher? ;D