标题: sample mean vs population mean [打印本页] 作者: domani 时间: 2011-7-11 17:45 标题: sample mean vs population mean
I somehow associated using n-1 with computing the statistic for sample. Apparently is not the case with finding sample mean. If so, what is the difference between formulae for "sample mean" and "population mean"?作者: suyash1989 时间: 2011-7-11 17:45
Population mean is (Total Population / N)
Sample Mean is (Sample/n)
The sample is chosen from the population because you believe it's a good representation of the population. For exam purposes, you will be given the numbers.
The n-1 your referring to is different. You use that denominator when calculating the Covariance when given historical data. The removes the statistical bias. Use that denominator when you see a question in portfolio mgmt asking you to calculate Covariance
Covarance in Quant section uses the probability formula, which is slightly different.
