Final answer:
Observational studies measure variables without manipulating them, while experimental studies manipulate variables to establish cause and effect. Observational studies can identify correlation, while experimental studies can identify causation.
Step-by-step explanation:
An observational study is a type of nonexperimental scientific investigation where the researcher measures characteristics in a sample but does not manipulate or control variables of interest. Observational studies can identify correlations between variables and take place in real-world conditions.
An experimental study, on the other hand, is a type of scientific investigation that is performed under controlled conditions. It manipulates an independent variable and measures dependent variables. Experimental studies can identify causation by controlling all possible variables.
Both types of studies involve measuring variables, but observational studies do not manipulate the independent variable and focus on natural variation, while experimental studies manipulate the independent variable and focus on controlling for random factors.