repeatcon.m
returns values in Fcontmat. Effect size estimate r(contrast) according to
Rosenthal et al. are returned in rcontmat. Neither the F-value nor the
r(contrast) gives you information about the direction of the trend!
repeatmat: is a data array arranged such that channels/sensors etc.
are represented as rows, subjects as columns and conditions
in the 3. dimension. Arrange the conditions in such a way that
they correspond to the trend.Function sort4trend then arranges it
in an appropriate way for contrast analysis.
weights: always have to sum up to zero. Following weights for orthogonal
contrasts (linear, quadratic, cubic) are suggeste by Rosenthal
& Rosnow (1985).
2 conditions:
lin: [-1 1]
3 conditions:
lin: [-1 0 1], quad: [1 -2 1]
4 conditions:
lin: [-3 -1 1 3], quad: [1 -1 -1 1], cub: [-1 3 -3 1]
5 conditions:
lin: [-2 -1 0 1 2], quad: [2 -1 -2 -1 2], cub: [-1 2 0 -2 1]
6 conditions:
lin: [-5 -3 -1 1 3 5]
quad: [5 -1 -4 -4 -1 5]
cub: [-5 7 4 -4 -7 5]
7 conditions:
lin: [-3 -2 -1 0 1 2 3]
quad: [5 0 -3 -4 -3 0 5]
cub: [-1 1 1 0 -1 -1 1]
8 conditions:
lin: [-7 -5 -3 -1 1 3 5 7]
quad: [7 1 -3 -5 -5 -3 1 7]
cub: [-7 5 7 3 -3 -7 -5 7]
9 conditions:
lin: [-4 -3 -2 -1 0 1 2 3 4]
quad: [28 7 -8 -17 -20 -17 -8 7 28]
cub: [-14 7 13 9 0 -9 -13 -7 14]
10 conditions:
lin: [-9 -7 -5 -3 -1 1 3 5 7 9]
quad: [6 2 -1 -3 -4 -4 -3 -1 2 6]
cub: [-42 14 35 31 12 -12 -31 -35 -14 42]
Function created according to R. Rosenthal & R. Rosnow (1985). Contrast
analysis: Focused comparisons in the analysis of variance. Cambridge: CUP.
Further resource: R. Rosenthal, R. Rosnow & D.B. Rubin (2000). Contrasts
and effect sizes in behavioral research: a correlational approach. Cambridge:
CUP.