#1
|
|||
|
|||
Another Probability Question
If you have 20 coins, 9 of them quarters and 11 nickels. You select 5 coins at random. What is the mean and variance of the number of quarters selected?
Thanks. |
#2
|
|||
|
|||
Re: Another Probability Question
Mean: 5 * (9/20)
Variance: 5 * (9/20) * (1 - 9/20) * (20 - 5)/(20 - 1) |
#3
|
|||
|
|||
Re: Another Probability Question
why?
|
#4
|
|||
|
|||
Re: Another Probability Question
Why not? [img]/images/graemlins/laugh.gif[/img]
Is that a homework question? |
|
|