Skip to main content

Table 2 Degrees of freedom associated with common statistical tests.

From: The problem of pseudoreplication in neuroscientific studies: is it affecting your analysis?

Test Degrees of Freedom
T-test  
   Independent n1 + n2 - 2
   Paired n - 1
One-way ANOVA G - 1 and n - G
Two-way Anova  
   Main effect of A G A -1
   Main effect of B G B -1
   A × B interaction (GA -1)(GB -1)
   Error n - G A G B
One-way RM-Anova  
   Between subjects G - 1
   Error (n -1)(G -1)
Two-way Mixed † ANOVA  
   Between subjects n(G - 1)
Groups    G-1
Error    G(n-1)
   Within subjects N - nG
Obs    Obs - 1
Group × Obs Interaction    (G - 1)(Obs - 1)
Error    N - nG - G (Obs - 1)
Linear Regression 1 and n - 2
Chi-square (R - 1)(C -1)
  1. n1 = sample size of group one; n2 = sample size of group two; n = total sample size; N = total number of observations (equal to n × Obs); G = number of groups; G A = number of groups for Factor A; G B = number of groups for Factor B; Obs = number of repeated observations on the same subject; R = number of rows; C = number or columns. † "Mixed" refers to the presence of both between and within subjects effects, and should not be confused with mixed effects models described in the text.
Back to article page

BMC Neuroscience

ISSN: 1471-2202

Contact us