In a controlled experiment, what is it called when results show no effect of the independent variable?

• A. A positive effect
• B. A null result or no effect
• C. A significant finding
• D. A correlated outcome

Answer: (B)

In a controlled experiment, the goal is to see whether changing the independent variable produces a change in the dependent variable. When the analysis shows that there is no measurable change in the dependent variable in response to the manipulation, that outcome is called a null result or no effect. It means the data don’t provide evidence that the manipulation had any impact under the conditions tested, which could be because there truly is no effect, or because the study wasn’t sensitive enough (for example, due to a small sample size or measurement noise).

A positive effect would mean the manipulation caused a detectable change in the dependent variable. A significant finding would indicate that the observed effect is unlikely to be due to chance. A correlated outcome suggests a relationship between variables, which does not necessarily imply a causal effect from the manipulation in a controlled experiment.