Probability using Combinations

[SchoolProjectsGo]

sounded like you were gonna choose which 3 of the 8 live or die, hahahaha

[Maisun1123581321]

What my prof couldn't teach me over a 3 hours long lecture, you did it in 9 minutes!

[m3tm4n]

Can you calculate the total outcome with the combination formula??

[Tikimatuka]

Sal really IS the god of probability

[bogdandospinescu12]

There is sth wrong to the demonstration. If we the same formula to find out for example the probability of getting 4 heads in 8 flips, than we have 27%, and is clearly that the probability should be 50%

[GR530]

I IS STUPID

[LazLoGirL]

..this actually helped.. thank you :)

[aew782]

when you where doing 8x7/2*8 then went to 2*3 x 7/2*5 why dose the rule of exponents (a*-b*) not work when you do that. it gives me 2*-5 it's not correct what am i doing wrong when im simplifyin because thats a rule when you divide exponents

[Asmor]

@aew782 Subtract the same number from the exponents on both the top and bottom. Just to keep things clean, let's say it's just 2^3/2^8 = 2^(3-3)/2^(8-3) = 2^0/2^5 = 1 / 2^5.

Another way to understand is to expand them out. 2^3/2^8 = (2x2x2)/(2x2x2x2x2x2x2x2). Then you just cancel top and bottom and you're left with 1/2x2x2x2x2 = 1/2^5

Hope that helps!

[aew782]

@Asmor Thank you !

[polaroidfair]

who noticed that this Sal guy teaches everythg..maths, physics? i noe i did

[bhz10]

this... confused.... the FUCK.... out of me.

[Recordscience]

@bhz10 watch previous videos too

[DawnBreaker1100]

@bhz10 Yea, you need to watch the rest to understand this. When he refers to other videos there's probably something you have to watch in the past videos to get what he's talking about.

[Sameer3292]

I like turtles !

[atomikrobot300099]

You can your binomPDF( function on your "average" graphing calculator to do this @8:51...

[nightmare4eVerr1]

the question would have said then "probability of getting 3 consecutive heads" "exactly 3 heads" means the combination can be of any order (as sal has done) but it should not exceed or be lower than 3

[PFloydism]

@nightmare4eVerr1 thats wrong, they dont need to be consecutive using combinations (if you heads were on the 2,4 and 8th throw this is still valid, they do not need to be consectutive)

[janbaz125]

Does anyone know the answer

Bob arrives to work on time with probability 0.70, while Caroline arrives on times with probability 0.80. The probability they both arrive on time is 0.60.

AWhat is the probability that at least one of them arrives on time

B)What is the probability that exactly one will arrive at work on time?

[bobby123greenhalgh]

ask your teacher at school how to do probability trees, You can solve this problem using probability trees as your method.

[bobby123greenhalgh]

Also just a quick tip for all those out there that don't want to simplify factiorials 8!/3!= 8C3 which is a shortcut on many scientific calculators.

[thedisguisedmaster]

Ok, now I got combinations. During the combinations video I was totally confused.

[dave93vert]

will be alot clearer if u mention that the denominator is the "sample space".

[ZHAOFEIXIANG]

tnnx for the tutorial mate, helped alot

[shazaduh]

"I am the god of probability" hahaha...

[MrSandyRaina]

The Probalility of Chosing three flips out of eight is 21.75%. But these three flips can also result in tails also. I guess we need to divide it by half to get three heads exactly. Answer awaited.

[vdesidevil]

I agree with Mr.Raina. I believe Mr.Khan is missing here something. 21.75% is the answer for getting any 3 combination (i.e HHH, HHT, TTT...etc) If you look at begining, question actually asking for "What is the probabilty of getting excatly 3 heads (HHH) out of 8 flips?" Waiting for Mr.Khan's response.

[TICOMMECA]

@vdesidevil

if you look closely, he tosses it 8 times, so the outcome must be 8 also, it maybe HHHTTTTT or HTTHHTTT, not HHH or HHT, the question is 3 heads out of 8 tosses.

[charutalwar]

Wow! Thank you so much...I got it...n i cant believe it!

[ULTRAFORCEp90mex]

thanks it helps a lot

now i get it

[bubblesnuggles]

its so confusing...the way u explained just confuses me alot

[safithegr8]

Dude u confused me a lot... i think i gotta watch your permutation and combinations video again, and also binomial theorem b4 them!!..

[Stalingrad17]

thanks

[maxpurdy]

it helps a lot!