Chapter 4 · Sampling · Slide 131/274

Stratified Sampling

The population is first divided into non-overlapping strata. Then a (dis-)proportional share is drawn at random from each stratum. Elements within a…

4.2 · Probability Sampling Requires knowledge about the population

Stratified Sampling

11012

246

7811

359

→

Sample

210

The population is first divided into non-overlapping strata. Then a (dis-)proportional share is drawn at random from each stratum. Elements within a stratum should be similar to one another.

Good for

Highlighting a particular subgroup within the population Observing relationships between two or more subgroups Representative sampling of even the smallest and least accessible subgroups Higher statistical precision

Proportional

Stratum	A	B	C
Population size	100	200	300
Sampling fraction	½	½	½
Sample size	50	100	150

Disproportional

Stratum	A	B	C
Population size	100	200	300
Sampling fraction	⅕	½	⅓
Sample size	20	100	100

QUESTIONSTAR · Dr. Paul Marx 131 / 274

To the full presentation