Complex Surveys

1
Complex Surveys

• Components of a complex survey random sampling
  ratio estimation stratification clustering.
• How to assemble above components into a complex
  survey?

2
Malaria in Gambia

• Malaria occurs in over 100 countries. More than
  40 of the people in the world are at risk.
• Malaria kills about 2 million people annually,
  mostly African children under the age of 5.
• Malaria is a serious health problem in Gambia.
• Malaria is transmitted by mosquito.
• Malaria morbidity can be reduced by using bed
  nets that are impregnated with insecticide.

3
Nationwide Survey on the Prevalence of Bed Net
Use in Rural Areas (1991)

• Sampling frame all rural villages of fewer than
  3000 people

Stage Sampling Unit Stratification Sampling Probabilities
1 District Region Proportional to district population
2 Village PHC/non-PHC Proportional to village population
3 Compound Random sampling
4
Estimating a Distribution Function

• Historically, sampling theory was developed to
  answer questions like What percentage of adult
  males are unemployed? or What is the total
  amount of money spent on health care in the
  United States? or What is the ratio of the
  numbers of exotic to native birds in an area?
• But Statistics other than means or totals may be
  of interest. For example, you may want to see the
  distribution of the midterm scores.