Quiz 2 - F Tests

what is an f test?

• an inferential statistic that uses the F distribution for determining if there is a significant difference among groups’ scores

• how many IVs are there for one-way, two-way, and three-way ANOVAs?

• what is a factorial ANOVA?

• amount of ivs

  • one-way: 1 IV

  • two-way: 2 IV

  • three-way: 3 IV

• factorial ANOVA: ANOVAs with at least 2 IVs

what is the difference between between-subjects design versus within-subjects design?

• between-subjects design: involves different subjects participating in different conditions

• within-subjects design: involve all subjects participating in all conditions

  • one-way within-subjects ANOVAs are ANOVAs with 1IV; participants are assigned to all conditions

• how do you calculate the df for one-way between-subjects ANOVAs?

  • how do you read the example result in APA format?

• numerator DF = g - 1 (g = # of groups)

• denominator DF = Error DF = g(n-1) where n = subjects / groups

• example result in APA format: F(2,27) = 4.03, p = .03

  • 2 = numerator DF; 27 = denominator DF

• how do you calculate the df for one-way within-subjects ANOVAs?

  • how do you read the example result in APA format?

• numerator DF = g - 1 (g = # of groups / time periods)

• denominator DF = Error DF = n-1 x g-1 where n = subjects / groups

• example result in APA format: F(2,27) = 4.03, p = .03

  • 2 = numerator DF; 27 = denominator DF

Practice Problem:

• One-Way Between-Subjects ANOVA:

  • IV = Pet Type

  • DV = anxiety

  • 3 Groups

  • N = 30

  • n = 10

• Question:

  • numerator df?

  • df error?