<prompt> A person wants to study a disease ;x; and fat consumption. He obtained data for number of people affected with ;x; from the government and the details of fat consumption from food industry. Type of study isEcological studyCross sectional studyPesiological studyExperimental study  <response>: Ecological correlations study. Unit of study is population results not applicable to individuals. Done in a small time frame. It is inferior to coho and case control. Reference: Parks textbook of preventive and social medicine,K.Park,21st edition,page no:59 22nd edition, pg no.60. 