1. ## Variance question

I'm not sure I understand this problem based on what I know of variance. Can someone help?

Suppose that 85% of all households bought in the last 4 months a product made by the Proctor & Gamble Corporation. If 386 households are selected at random, what is the variance of the number of households that bought in the last 4 months a product made by the Proctor & Gamble Corporation?

2. Originally Posted by dwhee
I'm not sure I understand this problem based on what I know of variance. Can someone help?

Suppose that 85% of all households bought in the last 4 months a product made by the Proctor & Gamble Corporation. If 386 households are selected at random, what is the variance of the number of households that bought in the last 4 months a product made by the Proctor & Gamble Corporation?
The number of households N in your sample that bought a product from P&G
has a binomial distribution B(386,0.85). The question is asking what is the
variance of a random variable with this distribution.

RonL

3. Originally Posted by dwhee
I'm not sure I understand this problem based on what I know of variance. Can someone help?

Suppose that 85% of all households bought in the last 4 months a product made by the Proctor & Gamble Corporation. If 386 households are selected at random, what is the variance of the number of households that bought in the last 4 months a product made by the Proctor & Gamble Corporation?
just understand what variance means in the dictionary and u'll figure it out. it seems like the difference of 85% of 386 or i may be wrong cause i didn't check the dictionary yet

4. Originally Posted by lorenzolama
just understand what variance means in the dictionary and u'll figure it out. it seems like the difference of 85% of 386 or i may be wrong cause i didn't check the dictionary yet
Wittgenstein wrote:

"Whereof one cannot speak, thereof one must be silent"