research methods

What consent is required for participants under 16?

Parent/guardian consent

What is a Type I error?

False positive (rejecting H₀ when true)

What does H₀ typically state?

"No relationship between variables in the population"

What α level is standard in psychology?

0.05 (p < .05)

What measure of central tendency for nominal data?

Mode only

What defines a one-tailed hypothesis?

Predicts direction of effect (A > B)

In an experiment, what is manipulated?

Independent Variable (IV)

What does effect size measure?

Strength/magnitude of relationship between IV and DV

What type of data do parametric tests need?

Interval or Ratio data (and normal distribution)

What data does chi-square test use?

Categorical (nominal) frequency data

How is a z-score calculated?

z = (X - Mean) / SD

What's the relationship between SD and variance?

SD = √Variance

What is the main limitation of using range?

Sensitive to outliers

In positively skewed data, mean is ______ median?

Greater than

What is statistical power?

Probability of correctly rejecting H₀ (1 - β)

Which BPS principle values "dignity and worth of all persons"?

Respect

What is a confound?

Variable related to both IV and DV

Which are probability sampling methods?

Random, Stratified, Systematic

What % of data within ±1 SD in normal distribution?

68%

What do expected frequencies represent in chi-square?

Frequencies if H₀ were true (by chance)

What is a Type II error?

False negative (missing real effect)

What does Standard Error measure?

Variability of sample means (SE = SD/√N)

Between vs Within subjects design difference?

Between=different groups; Within=same participants

What defines quasi-experimental research?

No random assignment (pre-existing groups)

What is a "medium" Cohen's d effect size?

d = 0.5 (small=0.2, large=0.8)

How is df calculated for chi-square association?

df = (rows-1) × (columns-1)

When is a binomial test appropriate?

Testing proportions in TWO categories

Interpretation of 95% CI [200ms, 250ms]?

95% confident population mean is 200-250ms

When is a sign test used?

Repeated measures with direction of change (+/-)

When use non-parametric tests?

Nominal/ordinal data OR parametric assumptions violated

When use bar chart vs histogram?

Bar chart for nominal/categorical data

What does IQR represent?

Middle 50% of data (Q3 - Q1)

Which power factor is NOT researcher-controlled?

Effect size (population property)

What must happen during debriefing?

Explain true purpose, allow questions, monitor distress

How are Likert scales treated statistically?

As ordinal (often analyzed as interval with caution)

Multinomial vs Chi-square Goodness of Fit difference?

Multinomial=equal proportions; GOF=specific proportions

Purpose of control group?

Baseline comparison (no IV) to isolate IV effect

What is sampling error?

Difference sample vs population due to chance

Advantage of one-tailed test?

More power to detect effect in predicted direction

Can ratio data be converted to ordinal?

Yes (can go down scales, not up)