Simple Variance Question
 

Can somebody calculate the variance for these two situations for me?

I'm a little rusty on my stats, and I think I'm going about it the wrong way

Situation 1:
Getting 1.5:1 on a coin flip

Situation 2:
Getting 6:1 on a single number, on a the roll of a die

Please show all steps.

Re: Simple Variance Question
 

V(x) = E(x^2) - E(x)^2

For the case of the die,
E(x) = 3.5
E(x)^2 = 12.25
E(x^2) = 15.16667
V(x) = 2.91667

Coin flip (where 0 is one side, 1 is the other)
E(x) = E(x^2) = 0.5
V(x) = 0.25

Re: Simple Variance Question
 

tyvm!

EDIT: errr... your values for E(x) are wrong, unless I'm missing something.

Re: Simple Variance Question
 

FWIW: I have the EVs calculated as:

1:
(1.5x-1x)/2 = 0.25x = E(x)

2:
(6x-5x)/6 = 0.167x = E(x)

Re: Simple Variance Question
 

[ QUOTE ]
Can somebody calculate the variance for these two situations for me?

I'm a little rusty on my stats, and I think I'm going about it the wrong way

Situation 1:
Getting 1.5:1 on a coin flip

Situation 2:
Getting 6:1 on a single number, on a the roll of a die

Please show all steps.

[/ QUOTE ]

Answered on Probability, where this problem belongs.

djames is answering a different question, namely the variance of the number rolled on the die, and the variance of a coin flip where heads=1 and tails=0. The OP wants the variance of money won for a bet of size x.

Re: Simple Variance Question
 

Thanks again, Bruce.

Re: Simple Variance Question
 

Mods can feel free to delete this thread.

Apparently it's in the wrong forum.