A psychologist finds a significant difference between two conditions. She is very happy, and repeats the study. This time, she finds no significant difference. She runs the study ten additional times, failing each time to find a significant difference. There is a good chance that the significant difference she found the first time
A) was a Type I error
B) was a Type II error
C) could have been either a Type I or Type II error

Question

Quizplus · Accepted Answer

A Type I error occurs when a researcher incorrectly rejects a true null hypothesis, meaning they find a significant difference when there is none. The psychologist's inability to replicate the significant difference in subsequent studies suggests the initial finding may have been a false positive, indicative of a Type I error.

A Psychologist Finds a Significant Difference Between Two Conditions