Dychwelyd yr amcangyfrif o' r amrywiant o boblogaeth a seilir ar sampl gan ddefnyddio' r gwerthoedd rhifol i gyd mewn colofn o gronfa ddata a phenodir gan set o amodau.
Returns the estimate of the variance of a population based on a sample using all numeric values in a column of a database specified by a set of conditions.