When you say:
"If you flip 9 times a coin and get 9 faces then at the 10Th time you flip
it the odds of getting a tail are much higher than the odds of getting a
face."
you are entirely wrong.

When you say:
"the chance to get 10 faces straight are lower than the chances to get 9
faces and 1 tail in 10 coin flips."
you are right, but only because there are 10 sequences in which you can get
9 faces and 1 tail.
If you have had 9 faces in the first 9 flips, the probability of getting 10
faces is exactly the same as getting 9 faces followed by 1 tail.
--
David Biddulph

Raul Sousa wrote:
If you flip 9 times a coin and get 9 faces then at the 10Th time you
flip it the odds of getting a tail are much higher than the odds of
getting a face. At any flip the chances are 50/50. But, the chances
to get 10 faces straight are lower than the chances to get 9 faces
and 1 tail in 10 coin flips.
I am sure there must be a way to calculate this probabilities in
excel. Just don't know how to and appreciate any help.


"Mike H" wrote:

Hi,

The changes to have 1 or 0 are 50/50. In this case there is more 1
than 0 (5Vs2). So the chances that the next number is a zero are
bigger than the chances that the next number is 1.


That's incorrect because it implies that (say) a coin has memory and
if we flip 10 consecutive heads the next is more likely to be tails
which it isn't, the chance of the next being tails is exactly the
same as for the previous 10 flips 50/50.

Mike

"Raul Sousa" wrote:

Thanks for your replay Max.
it could be a good idea. Unfortunately I think it is not correct.
The changes to have 1 or 0 are 50/50. In this case there is more 1
than 0 (5Vs2). So the chances that the next number is a zero are
bigger than the chances that the next number is 1.
I just don't know a formula to calculate these odds.


"Max" wrote:

Probability that its a 1:
=COUNTIF(A2:A8,1)/COUNTA(A2:A8)

Similarly, the probability that its a zero:
=COUNTIF(A2:A8,0)/COUNTA(A2:A8)

Alternatively, since Pzero + Pone = 1
as the data comprises only zeros or 1s (in this instance)
Pzero = 1 - COUNTIF(A2:A8,1)/COUNTA(A2:A8)

any good? hit the YES below
--
Max
Singapore
http://savefile.com/projects/236895
Downloads:27,000 Files:200 Subscribers:70
xdemechanik
---
"Raul Sousa" wrote:
I am trying to calculate probabilities in excel but I don't
really know which functions to use.
Lets say I have only two possible outcomes 1 and 0. So far the
outcome was as follow:
1
0
1
0
1
1
1

Which are the odds to get 1 and to get 0?
Which formula can calculate this?