Difference between binompdf and binomcdf?

[Timtasticle]

...is?

[Collin Li]

Yep!

binompdf(n,p,x) = Pr(X = x)
binomcdf(n,p,x) = Pr(X ≤ x)

The "c" stands for cumulative, and that's why it's Pr(X ≤ x). If you want to find Pr(X ≤ 4), you'd accumulate the probabilities of getting X = 0, 1, 2, 3, 4.

[rustic_metal]

...is?

i believe binompdf is for one value (i.e. Pr(X=x)) whereas binomcdf is cumulative (i.e. Pr(X>x))

not 100% sure though

[Timtasticle]

Aaaah I love you FSN.

[rustic_metal]

damnit beaten.

was i even right?  :?

[Toothpaste]

damnit beaten.

was i even right?  :?

First one's right, second one's wrong.

binomcdf(n,p,x) = Pr(X ≤ x)

You had the arrow the other way. But cool that you've looked into it.

[kido_1]

Binomcdf is usually used with the terms 'at least' (1-binomcdf...)

Binompdf is usually used for exact. For instance 3 out of 5.

[bilgia]

does everyone have 'prcheat' the calc program??? its a time saver, especially for multi choice qns

[Toothpaste]

I only have Factor 9 .. cbf putting 10 on. Lol.

Is Prcheat necessary?..

[bilgia]

pr cheat is very easy to use
u have options binomial, normal, std normal etc...
and then u input mean, s.d, no of elements etc...
and then u can choose >,=,>=,<= and so forth...
no need to manually do anything

[maxleng]

I only have Factor 9 .. cbf putting 10 on. Lol.

Is Prcheat necessary?..

ive never actualy used it on a Q, better to do it manualy so you practise for the MC where the answers arent decimals and for the Qs where you have to show your working

when i first got it i thought "awsome" but have never even used it...

[kido_1]

I actually don't mind factor 9.
It is a time saver. I do not have Pr cheat though.

[Collin Li]

does everyone have 'prcheat' the calc program??? its a time saver, especially for multi choice qns

IMO, PrCheat is a waste of time. If you know how to use your calculator, it is faster, plus you can do some questions that are not possible on PrCheat (e.g: the ones where you "n" is unknown in binomial).

PrCheat does not give you easy access the value that it returns from your calculations, so you are not sure if your accuracy too. I like using binompdf/binomcdf/invNorm/etc. because I can press Ans to use it with some further calculation down the track.

[kingmar]

Really only two programs are useful, I find. PrCheat and Factor9.

I'm sure most people have Factor 9.

PrCheat, does (as its name suggests) probabilities.

I actually use the inbuilt functions. I find it faster and I can use them as official working out for probability questions.

You can't write "PrCheat" as working.
Otherwise, as an alternative to the inbuilt, it's extremely handy. Just remember to break the program by pressing "ON" - quitting normally has crashed my calc and resetted my RAM (deleting itself in the process) a couple of times...

EDIT: Ah, coblin, is there anything mathematics related you DON'T know?

[kido_1]

Phew, I was wondering what Pr cheat was.
Yet different people may feel comfortable doing different things.