Expected number and standard deviation

[glenn]

I have absolutely no idea even how to set this one up. If somebody could please help me I would greatly appreciate it. Thanks.

Assume that in Fizzo-Cola's new bottle cap game, the probability that a bottle will have a winning bottle-cap is 0.25. Suppose you buy 9 bottles of Fizzo-Cola.

A) Find the expected number of winning Fizzo-Cola bottle-caps.

B) Find the standard deviation of the number of winning Fizzo-Cola bottle-caps.

 

[pka]

Assume that in Fizzo-Cola's new bottle cap game, the probability that a bottle will have a winning bottle-cap is 0.25. Suppose you buy 9 bottles of Fizzo-Cola.
A) Find the expected number of winning Fizzo-Cola bottle-caps.
B) Find the standard deviation of the number of winning Fizzo-Cola bottle-caps.

This is a binomial distribution.
The expected number is \(\displaystyle pN\) and standard deviation is \(\displaystyle \sqrt{p(1-p)N}\)

 

[glenn]

so it is 0.25*9?

 

[pka]

so it is 0.25*9?

Well in this question \(\displaystyle p=0.25~\&~N=9\) what do you think?

 

[glenn]

lol sorry...thanks, im just not a big statistics person i have a hard time with this stuff