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.