Single-factor designs

Question 1

What is some vocabulary to know for this section?

Answer 1

• Factor: the independent variable
• Level: the number of “states” of the variable you are testing

Question 2

Matched groups, 1 factor

Answer 2

Blagrove (1996): Matched participants on their normal sleep duration. Will sleep-deprived people be
influenced by misleading questions?
Factor = amount of sleep
Levels = adequate sleep / inadequate sleep
Analysis = t-test for dependent groups

Question 3

Independent groups, 1-factor

Answer 3

Example: Blakemore and Cooper (1970) raise two-week-old cats in two visual environments: one see
only horizontal stripes, others see only vertical stripes.
Factor = type of visual environment
Levels = horizontal stripes / vertical stripes
Data analysis: t-test for independent groups

Question 4

1 factor, nonequivalent groups

Answer 4

Non-equivalent groups: when matching AND random assignment is infeasible.
Knepper, Obrzut & Copeland (1983): Are gifted children good at social and emotional problemsolving,
compared with average-IQ children?
Factor = IQ
Levels = Average IQ / above-average IQ
Analysis: T-test for independent groups

Question 5

1-factor, within-Subjects

Answer 5

Lee & Aronson (1974): Will children shift their balance to moving visual stimuli as if their balance has
shifted?
Factor = visual stimuli
Levels = forwards / backwards
Analysis = t-test for dependent groups

Question 6

multilevel designs

Answer 6

• All the previous designs have included only 2 levels.
• Adding more levels adds more sensitivity and can show the true relationship between variables.
• Can be within or between subject designs
• Additional levels reduce your statistical power: o More levels = more comparisons = less degrees freedom = need more participants