Simple Effects: WITHIN and MWITHIN Keywords (MANOVA: Univariate command)

A factor can be nested within one specific level of another factor by indicating the level in parentheses. This process allows you to estimate simple effects or the effect of one factor within only one level of another factor. Simple effects can be obtained for higher-order interactions as well.

Use WITHIN to request simple effects of between-subjects factors.

Example

MANOVA YIELD BY SEED(2,4) FERT(1,3) PLOT (1,4)
  /DESIGN = FERT WITHIN SEED (1).

• This example requests the simple effect of FERT within the first level of SEED.
• The number (n) specified after a WITHIN factor refers to the level of that factor. The value is the ordinal position, which is not necessarily the value of that level. In this example, the first level is associated with value 2.
• The number does not refer to the number of partitioned effects (see PARTITION Subcommand (MANOVA: Univariate command)).

Example

MANOVA YIELD BY SEED(2,4) FERT(1,3) PLOT (3,5)
 /DESIGN = FERT WITHIN PLOT(1) WITHIN SEED(2)

• This example requests the effect of FERT within the second SEED level of the first PLOT level.
• The second SEED level is associated with value 3, and the first PLOT level is associated with value 3.

Use MWITHIN to request simple effects of within-subjects factors in repeated measures analysis (see MWITHIN Keyword for Simple Effects (MANOVA: Repeated Measures command)).