Stats Part 5 Flashcards
(23 cards)
What is random assignment?
Assigning subjects to treatment groups using a chance process to reduce bias.
What is a control group?
A group in an experiment that does not receive the treatment, used for comparison.
What is a placebo?
A fake treatment given to control for psychological effects.
What is blinding?
Keeping participants or experimenters unaware of group assignments to reduce bias.
What is a confounding variable?
A variable that affects both the independent and dependent variables, potentially misleading results.
What is stratified sampling?
Dividing a population into subgroups and sampling from each.
What is cluster sampling?
Dividing the population into clusters and randomly selecting entire clusters.
What is systematic sampling?
Selecting every nth individual from a list.
What is convenience sampling?
Using a sample that’s easy to access but may not be representative.
What is sampling bias?
Bias introduced when the sample is not representative of the population.
What is power analysis used for?
To determine the sample size needed to detect an effect of a given size.
What inputs are needed for power analysis?
Effect size, alpha level, power level, and variance.
What is a typical target for statistical power?
80% — meaning an 80% chance of detecting a true effect.
Why is over-reliance on p-values problematic?
P-values don’t indicate effect size or practical significance.
What is the difference between estimation and testing?
Estimation provides a range; testing gives a yes/no decision about a hypothesis.
What is a Type S error?
Getting the sign of an effect wrong (e.g., saying it increases when it decreases).
What is a Type M error?
Overestimating the magnitude of an effect due to statistical noise.
How is a normal distribution visualized?
Using a bell-shaped curve with mean and standard deviations marked.
What is a QQ plot?
A plot to assess whether data follows a normal distribution.
What is a boxplot useful for in statistics?
Showing median, quartiles, and outliers of a distribution.
What is statistical inference?
Drawing conclusions about a population based on sample data.
Why is replication important in statistics?
To confirm findings and ensure results aren’t due to chance.
What is the difference between exploratory and confirmatory analysis?
Exploratory generates hypotheses; confirmatory tests them.
