Experimental Research

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Types of Experimental Research

1) True (classical) experimental design

Variations: Solomon 4-group design; Latin Square design

Solomon four group design: Helps control practice effect, used when measures of DV are unique, pre-tests are only used on 2/4 groups. Experimental group has treatment and control group does not

Latin Square design: Used when researchers are worried about test order effects

Seven parts: IV, DV, Pre and Post test of DV, Experimental group, Control group, Random assignment

2) Quasi-Experimental Research

Resembles true experimental design, usually has 6 of the 7 steps

Strengths --> greater external validity

Weaknesses --> low internal validity

Variations: one group and non-equivalent

One Group: Interrupted time series design and reversal design,

Non-Equivalent: not randomly selected

3) Pre-Experimental Designs

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