Stratified random sampling

STRATIFIED RANDOM SAMPLING

  • It is an accurate method because either over or under representation sampling is avoided.
  • First the study population is divided into strata, then sample is obtained from all of the individual strata.
  • 'Proportional allocation' is the method practiced for the stratified random sampling, where the number of sampling units selected is proportional to the number of each stratum.
    • Example: If 10% of animals from 10,000 animals in different strata (in five districts of Tamil Nadu) to be collected, as per the table it is to be followed.

S.No

Strata (region)

No. of animals

No. sampled (10%)

1.

Pudkkottai

3,000

3000x0.1 = 300

2

Namakkal

2,000

2000x0.1 = 200

3.

Thiruchirapalli

2,500

2500x0.1 = 250

4.

Krishnagiri

500

500x0.1 = 50

5.

Thanjavur

2,000

2000x0.1 = 200

Total

10,000

1,000

Last modified: Thursday, 22 September 2011, 12:12 PM