Replication of Studies in Psychology

Which of the following statements accurately defines a Type II error in null hypothesis testing?

If a researcher conducts a study with a small sample size and concludes there is no significant effect—even though a true relationship actually exists in the population—they have committed a Type II error.

A researcher is studying whether a new mindfulness app reduces stress. In reality, the app is highly effective. However, because the study only includes 10 participants, the researcher fails to find a statistically significant result and concludes the app does not work. Match each component of this scenario with the correct statistical concept.

Arrange the following events in the correct logical order to illustrate the causal chain of a Type II error, starting from the population reality and ending with the researcher's final conclusion.

You are designing a new clinical study to test if a specific nutrient supplement has a subtle, positive effect on cognitive recall in elderly participants. Because the expected effect size is small and the recruitment pool is limited, your primary goal is to propose a research design that minimizes the probability of a Type II error. Which of the following research plans best synthesizes methodological and statistical strategies to maximize your power to detect this effect?

A researcher is designing a study where failing to detect a true treatment effect would have much more dangerous consequences than accidentally claiming an effect exists. If the researcher prioritizes participant safety by specifically trying to minimize the risk of missing a real relationship that exists in the population, they are making a value judgment to focus on reducing the probability of a(n) _____ error.

In the context of statistical testing, a Type II error—which occurs when a researcher fails to detect an effect that actually exists—is also referred to as a _____ negative.

Match each core aspect of a Type II error in psychological research with its correct description.

A developmental psychologist conducts a study with 12 children to test whether a new interactive reading program improves vocabulary retention compared to standard reading methods. In reality, the interactive program is highly effective in the population. However, due to the small sample size, the study's statistical analysis yields $p = 0.14$, leading the psychologist to retain the null hypothesis and conclude that the interactive program has no effect. In this scenario, the psychologist has committed a Type II error.

An investigator is testing a new clinical program designed to reduce depressive symptoms. In reality, the program has a moderate beneficial effect in the population. However, the study is designed with a very small sample size, leading to an incorrect statistical decision. Arrange the events in the correct chronological and logical sequence to illustrate how this Type II error is produced, from the population reality to the final statistical error.