# sample or population

Below are monthly returns for Proctor & Gamble (PG) and Southern Company (SO): Monthly Returns PG SO December -0.8% 3.0% November 6.4% 3.8% October -0.7% 1.1% September 7.7% 2.2% August 5.6% 6.7% July 1.7% -1.9% The standard deviation of returns for PG and the covariance with SO are closest to: Std. Dev. PG A .03 B .03 C .04 D .04 Covariance A. .0005 B. .44 C. .0005 D. .44 guys what we should use in that question, is it the sample varaince or the Sigma…???

Of course the sample variance - you don’t have any population values.

how do u make sure that i should u the sample varaince, it is not stated anywhere that it is sample distribtuion, so i guess i should u the population varaince, calrify please, cuz i always get confused of what to cohoose …

amcrd1 - this is six months of data, so clearly a sample… a population would include the monthly returns on PG and SG since the day they were first publicly listed

and how would u know that these months are from the day they were firrst publicly listed!!!

someone do this on the BA II Plus real quick.

sample variance will lead to sample st dev sample st dev = sq rt of sum of squared devations divided by N - 1 step 1. find the mean for PG and SO step 2. find the deviations and square em 3: sum em all up 4. divide by 5 ( 6 01) COVAR i am not sure on

BlueCollarHero Wrote: ------------------------------------------------------- > amcrd1 - this is six months of data, so clearly a > sample… > > a population would include the monthly returns on > PG and SG since the day they were first publicly > listed Atually, it still wouldn’t be a population value. The population value has to do with an unobserved distribution. You will never see it.