A person found some correlation between dietary factors and a disease; he did this by collecting data from the food manufacturers and hospitals respectively, such a study is?

Social & Preventive Medicine

A person found some correlation between dietary factors and a disease; he did this by collecting data from the food manufacturers and hospitals respectively, such a study is?

A study is to be conducted with regards to the fat content…

'There has been a gradual increase in number of non-communicable disease cases…

All of the following are done to remove Confounding except