I

#### igor eduardo küpfer

Coin Flipper. The second is the number of coin flips each Coin Flipper

flips. The third column is the probability of each flipper flipping a

heads—these probabilities are different for each Flipper, but the same for

each Flipper's flip. I'm looking for a function that will display the number

of heads flipped for each Flipper, based on the data in the second and third

columns.

Wow. That came out more complicated than it should have been. Let me try

again.

A B C D

--------------------------------------

1 | ID #Flips p(Heads) #Heads

2 | 1 5 0.5

3 | 2 2 0.2

4 | 3 10 0.3

5 | 4 2 0.4

6 | 5 4 0.6

These are not necessarily fair coins. Some are weighted towards heads, so

that more than 50% of the flips will turn out to be heads, some are weighted

towards tails. I need to flip the coins for each flipper, and count the

heads.

For example, for the first flipper, I can enter the following in D2 and get

my result:

= (RAND()<C2) + (RAND()<C2) + (RAND()<C2) + (RAND()<C2) + (RAND()<C2)

But each of my flippers flips a different number of coins. I don't want to

have to manually enter "(RAND()<C2)" for each flip into the cell in column

D, and I don't want to have to use extra columns for individual flips[*]. Is

there a function or formula I can enter using a single cell that will flip

the exact number of coins? Ideally there'd be a function that looks like

this:

= COINFLIP(Number_Flips, Probability_Heads)

but any old solution would do.

[* The reason I don't want to use extra columns is that some of my flippers

flip hundreds of coins. That's too many columns for me to take up.]

--

all the best,

ed

Epitome:

Nice kid, but about as sharp as a sack of wet mice.

Email:

edkupfer. It's a gmail addy.