statistics - probability just q (b) thanks

[lost osprey]

statistics - probability just q (b) thanks

[radiant moth]

Ok so

Do you know any nice formulae for probability

[lost osprey]

ye

[radiant moth]

Especially with P(AnB) and P(AuB)

[lost osprey]

p(AUB) = P(A)+P(B) - P(AnB)

but still tho i dont get it rlly bc you have to rearrange stuff

do yk how to do it

[lost osprey]

?

[radiant moth]

Yep and

There’s one for P(AnB) when A and B are independent

Is this one you know? @lost osprey

[radiant moth]

Have u vanished

😠

[lost osprey]

srry

i was having a debate

people slandering religion

[radiant moth]

fair enough

[lost osprey]

ye i did that ik all the laws

just i still cant get it

bc you have to rearrange it

[radiant moth]

ok so just to write it explicitly

P(AnB) = P(A)P(B)

ok so

using that in our other expression

[lost osprey]

yes ik but you dont know p(b)

ye thats what i did

[radiant moth]

yeah were gonna get to that

[lost osprey]

use that equation in the other expression

other equation

[radiant moth]

so P(AuB) = P(A) + P(B) - P(A)P(B)

[lost osprey]

yet i did that but im going wrong somewhere

[radiant moth]

ok then sub in the values you know

[lost osprey]

ye thats exactly what i did

ok ill tell u what i got

[radiant moth]

0.7 = 0.5 + P(B) - 1/2 P(B)

0.2 = 1/2 P(B)

[lost osprey]

0.5P(b) = 0.5 + p(b) - 0.7

what do i do from there

[radiant moth]

simplify

0.5 - 0.7 is -0.2

it might be eaiser if i say

[lost osprey]

so what is p(b) lmao

[radiant moth]

instead of P(B) write x

[lost osprey]

i think im just misunderstanding smth

[radiant moth]

and see if you can solve it then

[radiant moth]

if i replace P(B) with x in this

what do i have

[lost osprey]

0.5x = -0.2 + x

ok safe

[radiant moth]

can you solve that?

[lost osprey]

why am i so dumb

[radiant moth]

idk

[lost osprey]

i literally had the expression as well

so annoying

[radiant moth]

yep

as soon as P comes in everyone forgets how algebra works 😭

[lost osprey]

perhaps it's bc i checked the ms when i wanted to check

and then they did it a weird way

probs bc a lot of work was needed to reach that so i didnt understand how they got there so quickly

my bad

[radiant moth]

yeah its nw

just unfamiliar

[lost osprey]

damn u in uni tho

what u studying

[radiant moth]

maths + stats

😭

[lost osprey]

Lmao

What’s some good preparation for statement or interview / exam stuff I could do

Or what could I do further reading or studying on

Or any like work experience or internship or super curriculum

[radiant moth]

interview for uni you can only really practise by like "thinking out loud"

or explaining out loud

try find ways to communicate what youre thinking

for entrance exam doing past papers is the best option, but for like MAT and TMUA i think they have basically all of AS pure as fair game

so id recommend only starting those at the end of y12

i would recommend doing whatever maths you feel interested in tho

like if you just wanna learn more about some random topic go for it

youtube videos, reading, doing maths challenges

[lost osprey]

Fair

I’m doing economics