**
Experimental Psychology**

**
Review, Exam II**

**Chapter 9 Using Statistics to Answer Questions**

Levels of measurement

Measures of central tendency (for nominal, ordinal, and interval/ratio sets of data)

Measures of variability (apply & understand SD and variance)

Abscissa vs. ordinate axes

Types of graphs bar and histogram

Standard normal distribution (characteristics)

Normal curve simulation of all frequency distributions with large enough sample

Correlational relationships

Degrees of freedom

*t*-test two uses

Significance level; 1-tailed vs. 2-tailed tests

Type I and Type II errors how to minimize

Effect size (correlations & t-tests)

**Chapter 10** ** Experiments with 2 Groups**

Structure of design

Group assignment (random or matched); if neither of these is used, groups are non-equivalent

Benefit of correlated groups designs - why they reduce error variability; know types (matched,

repeated measures, natural sets)

Statistic (t-test or ANOVA) = between groups/within groups (know relationship of between-

groups to within-groups)

*t*-test (independent samples and
correlated samples) correlated samples should have positive

correlation; requires interval or ratio level of measurement

Robustness of t-test (assumption of homogeneity)

Computer output interpretation; be able to identify the type of test and # participants

Importance of internal validity; cause/effect relationships

**Chapter 11** ** Experiments with Multiple Groups**

Structure of design know how to identify names (example: 2 x 3 ind. Grps. or one-way

design)

Group assignment

Statistic = between groups/within groups

One-way ANOVA (completely randomized and repeated measures) requires interval or ratio

level of measurement

Problems with repeated measures designs

Mean squares (SS/df), F ratio (between grps MS / within grps MS), and Post hoc tests (identify

where the difference is)

Asymptomatic

Computer output interpretation