Analysis Using SPSS

To test the equality of check variety effects, accession effects and to compare accessions with check varieties, treatment contrast analysis is to be performed therefore, for ease of understanding, recode the accession number and check variety as follows:

 Main Procedure is:  

Start →All Programs → SPSS for Windows → SPSS 15.0/ SPSS13.0/ SPSS10.0 (based on the version available on your machine) → Enter data in Data Editor → Analyze → GLM → Univariate → yld → [puts yld under Dependent list: ] → trt → [puts trt under Fixed Factor(s): ] → blk→ [puts blk under Fixed Factor(s): ]   Continue → Model... [Opens Model dialogue box] → Custom → Build Term(s) → Main effects →   [puts trt and blk under Model:] → Continue → Paste → in the syntax editor mode enter the contrast → Run All.

For performing analysis, input the data in the following format. 

{Here block is termed as blk, treatment as trt and yield as yld. It may, however, be noted that one can retain the same name or can code in any other fashion}.

 Following are the brief description of the steps along with screen shots.

·         Open Data editor: Start → All Programs → SPSS for Windows → SPSS 15.0/ SPSS13.0/ SPSS10.0

·         Enter data in SPSS Data Editor. There are two views in SPSS Data Editor. In variable view, one can define the name of variables and variable types string or numeric and data view gives the spreadsheet in which data pertaining to variables may be entered in respective columns. In the present case, we enter data in numeric format.

·         Once the data entry is complete, Choose Analyze from the Menu Bar. Now select Analyze → General linear Model → Univariate.

·       This selection displays the following screen.

·         Select yld and send it to the Dependent Variable box; trt and blk may be selected for Fixed Factor(s) box. After doing these the dialog box should be like this

• Select Model in the Univariate dialog box i.e. → Model... [Opens Model dialogue box] → Custom → Main effects → trt → blk → [puts trt and blk under Model:]. This selection displays the following screen.

·         Click Continue to return to the Univariate dialog box.

·         All possible pair wise treatment comparisons can be performed using the Button Options on the dialogue box. A click on Button Options, gives the option for estimated marginal means and display means for. From the left hand box, take the effect treatment in the Display means for. Then check the box Compare main effects and then there are 3 options for confidence interval adjustment viz. LSD(none), Bonferrnoni and Sidak. Any one of these 3 options can be selected. Default option is LSD(None). 

       A screen shot for these options is

·         Click Continue to return to the Univariate dialog box.

Since, here we want to test

i)        the equality of check variety effects, accession effects.
ii) compare accessions with check varieties.

This can be done using the contrast analysis.

To perform the contrast analysis one can use the following steps.

·    Click Paste in the Univariate dialog box to get the syntax editor. In the syntax editor mode define the contrast as:

/LMATRIX 'controls' trt 1 -1 0 0 0 0 0 0 0 0 0 0;

                                  trt 1 1 -2 0 0 0 0 0 0 0 0 0;

                                  trt 1 1 1 -3 0 0 0 0 0 0 0 0;

/LMATRIX 'tests' trt 0 0 0 0 1 -1 0 0 0 0 0 0;

                              trt 0 0 0 0 1 1 -2 0 0 0 0 0;

                              trt 0 0 0 0 1 1 1 -3 0 0 0 0;

                              trt 0 0 0 0 1 1 1 1 -4 0 0 0;

                             trt 0 0 0 0 1 1 1 1 1 -5 0 0;

                             trt 0 0 0 0 1 1 1 1 1 1 -6 0;

                             trt 0 0 0 0 1 1 1 1 1 1 1 -7;

/LMATRIX 'test vs controls' trt -2 -2 -2 -2 1 1 1 1 1 1 1 1;

·       This selectin displays the following screen

·       Click Run → All.

• To answer all the questions 1 to 4, the following syntax may be used after creating the data file.

UNIANOVA

  yld  BY blk trt

  /METHOD = SSTYPE(3)

  /INTERCEPT = INCLUDE

  /EMMEANS = TABLES(trt) COMPARE ADJ(LSD)

  /CRITERIA = ALPHA(.05)

/LMATRIX 'controls' trt 1 -1 0 0 0 0 0 0 0 0 0 0;

                                   trt 1 1 -2 0 0 0 0 0 0 0 0 0;

                                    trt 1 1 1 -3 0 0 0 0 0 0 0 0;

/LMATRIX 'tests' trt 0 0 0 0 1 -1 0 0 0 0 0 0;

                              trt 0 0 0 0 1 1 -2 0 0 0 0 0;

                              trt 0 0 0 0 1 1 1 -3 0 0 0 0;

                              trt 0 0 0 0 1 1 1 1 -4 0 0 0;

                             trt 0 0 0 0 1 1 1 1 1 -5 0 0;

                             trt 0 0 0 0 1 1 1 1 1 1 -6 0;

                             trt 0 0 0 0 1 1 1 1 1 1 1 -7;

/LMATRIX 'test vs controls' trt -2 -2 -2 -2 1 1 1 1 1 1 1 1;

  /DESIGN = blk trt .