10 replies to this topic

[Nearx]

I'm taking a quiz but its open book. I never got my book so that doesn't help much.

I came across one problem

If P(A) = .2, find P(A) (There's a line over the "A" in the last P(A) thing)

I dont want the answer to that problem, I just need to know how the heck to do it x.x
Can anyone help? Maybe give me an example problem to go off of?

[rizler]

this is probability? and the second A is like this?
_
A?

i think the forumula you are looking for if its probability is


P(A) = The Number Of Ways Event A Can Occur
The total number Of Possible Outcomes

am studying Maths in college 1st year
weve finished with probability but i think i can still remmeber some

Edited by rizler, 07 March 2011 - 10:56 AM.

[Nearx]

Yup but only on the second A. Then the second question is backwards. With the lined A first.

If P(-A)=.02 find P(A)

- is the "line"

This is my first college year in math too. We just finished probability and had to take a quiz on it xD
But yes that's the formula. I just don't understand completely how to execute it

I had to go turn in the quiz but I'd still like to know. I'm pretty sure I butchered those 3 P(A) questions x.x
I just hope I at least did ok on the rest of it all. UGH - math T___T

[rizler]

well to be honest to solve it your probably gonna have to right some stuff down on paper seeing as to do it on here would be hard

either use a TREE Diagram
OR
VENN diagram (i recommend this if decimals)

then label everything and plot in your numbers

[ToxicS]

Agh I learned this two semesters ago. Don't remember it now

[Nearx]

o.o

<.<
this is why I hate math xD

There's a similar problem like this on the board:

P(E) = 1/5 (fraction)

Step 1: P(-E) = 1-P(E) = 1-1/5=5/5-1/5=4/5
Step 2: P(E)/P(-E) = 1/5 / 4/5 = 1/4

Then the answer is 1:4 or 1 to 4

I keep thinking the P(A) one is similar to P(E).... I didn't have to use Tree or Venn diagrams for the E one so I'm a little confused =/
The teacher actually never went over the diagrams for this section...

[Boggart]

I think what it's asking is the same thing, the notation for P(E) is just different (and not usually used).

If the probability of A occuring is noted as P (A) then propability of A NOT occuring is P(Ᾱ).

0.2 can be represented as 2/10. So the chance of it NOT occuring is the remaining 8/10. Full work is:

1 - 2/10 =10/10 - 2/10 = 8/10.

No? yes? no?

[Nearx]

Sounds about right o-o
xD
I'm not sure what the answer was to that quiz but when I find out I'll look back here and compare =3
Thanks!!!

[Boggart]

I took this last year so if you need more help, feel free to ask more

[Ladida]

Stats memories And then you'll do the probability of something occurring/not occurring after something already occurred/did not occur. That's Baye's Theorem I think. Good luck!

[Nearx]

Ugh math is so frustrating x.x
Thanks for the help guys! I can use this for my unit test =3

Thanks Boggart! Will do