When the population variances are unknown and unequal,we estimate each population variance with its ____________________ variance.

Population Variances

A measure of the spread or distribution of a set of data points in a population, indicating how much the values differ from the mean.

Estimate

An approximation or informed guess of a quantity or value when the exact number is unknown or uncertain.

Sample Variance

A measure of the dispersion or spread of the sample data points around the sample mean, estimating the variance of the population from which the sample was drawn.