Question

complete the statements about observational and experimental studies.

observational studies □ extraneous variables and therefore provide evidence that a □ relationship exists between two or more factors.

experimental studies □ study variables and therefore provide evidence that a □ relationship exists between two factors.

Explanation:

For observational studies: They do not control extraneous variables (since they just observe without intervening), and the relationship they show is an association (because without controlling variables, we can't say causation, just that factors are associated). For experimental studies: They control study variables (by manipulating one variable and controlling others), and this allows them to show a causal relationship (since controlling variables helps establish cause - effect).

Answer:

Observational studies $\boldsymbol{\text{do not control}}$ extraneous variables and therefore provide evidence that a $\boldsymbol{\text{correlational (or associative)}}$ relationship exists between two or more factors.

Experimental studies $\boldsymbol{\text{control}}$ study variables and therefore provide evidence that a $\boldsymbol{\text{causal}}$ relationship exists between two factors.