ek letter o (read as sigma ) is used to denote a po o o2 denotes a population variance. The populati ed as N E(X, - H)?

In the equation of standard deviation, I don't understand n-1.

ek letter o (read as "sigma" ) is used to denote a poo o2 denotes a population variance. The populatied asNE(X, - H)?i=1Nre the difference between each point and they the number of points, and take the squareis used to denote a sample standard deviatioance. The sample standard deviation is defiE(x, -X2nisnosi=1n - 1gaolddard deviation is measured in the same unce is measured in squared units of the daandard deviation of a set of housing expe