All of the following are analytical epidemiological studies except-
Analytical studies include: Ecological or correlational-with populations as a unit of study Cross-sectional or prevalence-with individuals as a unit of study Case-control or case reference-with individual as a unit of study Coho or followup-with individual as a unit of study (refer pg no:62 park 23rd edition)
Coho study
Case - control study
Ecological study
Field trial
Epidemiology