Studies involve naturalistic observation and case studies; studies involve the manipulation and control of variables.

Descriptive studies involve naturalistic observation and case studies; experimental studies involve the manipulation and control of variables.

Explanation:

Descriptive studies seek to understand a social phenomenon by using qualitative data that can be obtained through observation or interviews. The results of the study are presented as thick descriptions. Researchers don't seek to establish correlations such as cause and effect with these type of studies.

Experimental studies seek to find a relationship between two or more variables, for which they involve the manipulation and control of variables as a way to asess the influence of one variable over another.