Statistical Power Flashcards
(8 cards)
What is statistical power?
The probability that a test correctly detects a real effect — i.e., it rejects a false null hypothesis.
What kind of error does statistical power help avoid?
Type II error (failing to detect a real effect).
How does effect size (ES) influence power?
Larger effect sizes are easier to detect, so power increases with effect size.
How does sample size (n) influence statistical power?
Larger sample sizes increase power by improving precision.
How does background variation (σ or σ²) affect power?
More variation lowers power because it makes real effects harder to detect.
What is a common value for significance level (α), and what happens if you increase it?
Commonly α = 0.05; increasing it (e.g. to 0.10) increases power but also raises the chance of a Type I error.
How does the type of statistical test used affect power?
Some tests are more sensitive or better suited to the data, which can increase or decrease power.
Why is adjusting α important in studies with low replication, like environmental impact assessments?
Because power is low in such studies, increasing α (e.g. to 0.10) helps detect real effects more reliably.
