A researcher compared the mean IQ scores of randomly selected government and private school students and arrived at conclusion that private school curriculum has significant positive effect on intelligence of students as compared to that of the government school. This study can be categorized as:

A) Experimental

B) Ex-post facto

C) Historical

D) Case study

Answer: B

Explanation: This study is an example of ex-post facto research because the researcher is comparing groups that already differ on the independent variable (school type). The researcher does not manipulate the independent variable but studies its effect on the dependent variable after the fact .