Conditional Probability Example : ExamSolutions

[franciscojurado0]

THANK YOU SOOOOOOOOO MUCH! i did the first one myself and it went correct, did the first one based on all the things I learnt from your other videos! As I said before in an another vid, your a math's god!!

[ExamSolutions]

@franciscojurado0 well done

[giftowercom]

thanks!

[p6subhrap]

you are my life saver :D

[1995a1995z]

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 :-)

[daphniek1]

thank you so much. The video is very helpful!

[ExamSolutions]

@daphniek1 Cheers

[SparkyChelada]

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 :)

[ExamSolutions]

@SparkyChelada Thanks for your comment. Pleased to know you are grasping this tricky topic. It's all in the notation as you said.

[4xEVERMORE]

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.

[ExamSolutions]

@4xEVERMORE That's ok. I made the question up as a dedication to my wife Susan who is a teacher.

[chocobelge4]

Thank you for mentioning that the P(L) is wrong ... My teachers never mentioned it !

[ExamSolutions]

@chocobelge4 Common and irritating mistake

[bollywoodmassive]

Great video! Would it be okay if i wrote the probabilites as a fraction on the tree diagrams? for e.g. if i wrote p(A) = 3 over 10 ?

[ExamSolutions]

@bollywoodmassive of course

[bollywoodmassive]

@ExamSolutions silly question but was curious to know, thanks!

[muhaimen123]

Hi do you do tuition near central london ?

[ExamSolutions]

@muhaimen123 Watford, Hertfordshire.

[MrAlix777]

thanks for be nice and sharing

[MEGIDIOT]

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.

[ExamSolutions]

@MEGIDIOT Please read my homepage on my website where it says ActionAid and click on the link.

[Ziaan06]

How do you multiplied it by yourself?

[redrose11123]

Please be my teacher!!!!!!...Thank you sooooo sooooo sooo much

[ExamSolutions]

@redrose11123 Thank you for the complement.

[jammy123ism]

thanks man!

[ExamSolutions]

@jammy123ism Thanks for sharing

[jatras1234]

@ExamSolutions is that the Questions in the exams of A,s in january

[alfatourist]

I enjoy your lectures. You are gifted. Thanks for sharing.

[ExamSolutions]

@alfatourist Thank you

[ComplicateProbabili]

i have seen several methods in finding the conditional probability , by using the bayes theorem and tree method as illustrated or in which values(population) is assumed to find the probability, is it correct ? which is the best? ta

[ComplicateProbabili]

is susan going to work or school ?

[ExamSolutions]

Susan is going to work at school, she is a teacher. lol

[ComplicateProbabili]

:) .. anyway nice example and thanks f

[zowyadoinbeb]

can you also use Bayes' Thm for part two? If so, wouldn't the numerator need to be multiplied by P(Route A)?

[ExamSolutions]

I did use Bayes Theorem. The numerator is P(A and L) which is P(A) x P(L|A)

[kikzor]

Oh alright I get it, thanks

[kikzor]

Wouldn't it be P(A|L) on the tree diagram and P(L|A) used in (ii)?

[ExamSolutions]

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.