Review t-tests

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# Review t-tests - PowerPoint PPT Presentation

Review t-tests. Single-sample t-test (df = N – 1) Independent samples t-test (df = (n 1 – 1)+(n 2 – 1) ) Related or paired-samples t-test (df = N – 1). ANOVA formulas. One-way ANOVA df total = N – 1 df between = k – 1 df within =  (n – 1) or N – k. Repeated-measures ANOVA

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## PowerPoint Slideshow about ' Review t-tests' - raven

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Presentation Transcript
Review t-tests
• Single-sample t-test (df = N – 1)
• Independent samples t-test (df = (n1 – 1)+(n2 – 1) )
• Related or paired-samples t-test (df = N – 1)
ANOVA formulas

One-way ANOVA

dftotal = N – 1

dfbetween = k – 1

dfwithin = (n – 1) or N – k

Repeated-measures ANOVA

dftotal = N – 1

dfbetween = k – 1

dfwithin = N – k

dfbetween subjects = n – 1

dferror = dfwithin – dfbetween subjects

One-way ANOVA Repeated-measures ANOVA

Two-way ANOVA

dftotal = N – 1

dfbetween = k – 1 (or # cells -1)

dfwithin = N – k (or  (n-1) )

dfA = k – 1 (# rows – 1 for factor A)

dfB = k – 1 (# columns – 1 for factor B)

dfAxB = dfbetween – dfA - dfB

Effect size analyses
• Variance accounted for (r2)
• Small >.01
• Medium >.09
• Large > .25
• Paired samples t-test
• CI = MD ± t*(sMD)
• Cohen’s d
• Variance accounted for (r2)
• ANOVA: effect size = eta2
• z-test
• CI = M +/- z*(σM)
• One-sample t-test
• CI = M +/- t*(sM)
• Independent t-test
• CI = M1 – M2 +/- t*(sM1-M2)
• Cohen’s d
• Small >.2
• Medium >.5
• Large > .8
Other formulas
• Goodness of fit chi-square
• Frequency table of data
• Observed frequencies (fo)
• Compare to null hypothesis
• Expected frequencies (fe)
• Expected frequency
• fe = pn
• Chi-square equation
• df = C – 1, where C = # of categories