Sections

Using at() for sections

The Variance header line has been replaced by the RESIDUAL statement.

A typical experiment has 1 section. However, when combining results from several experiments into one analysis, we would have a section for each experiment. Then each experiment will have an error structure with its own variance. While there may be correlations among residuals within a section, are independent across sections.

Example

The following variance structure lines relate to an analysis three variety trials with common entries. It is assumed the data is sorted by experiment and that there is a complete grid of plots for each experiment although the experimental layout (number of rows and columns) may differ.

 met test run
  seq
  col 15     # Actually 12 12 and 15 for the sites respectively
  row 34     # Actually 34 34 and 28 for the sites respectively
  chks 7
  test 336
  geno 337
  yld 1  !*.01
  site 3
 metS0.dat   !section site
 yld ~ site chk.site ,
  !r at(site,3).row .02 at(site).col .90 .40 .036 coruh(site).test
 residual at(site).ar1(col).ar1(row)

Now

 at(site).ar1(col).ar1(row)

is shorthand for

 at(site,1).ar1(col).ar1(row) at(site,2).ar1(col).ar1(row) at(site,3).ar1(col).ar1(row)

and the longer form is required if the same spatial correlation structure is not required at each section. For example

 at(site,1).ar1(col).ar1(row) at(site,2).ar1(col).id(row) at(site,3).ar1(col).ar1(row)

could be written as

 at(site,1,3).ar1(col).ar1(row) at(site,2).ar1(col).id(row)

Return to index