sp(pow) of cov parm in covariance estimate output table in proc mixed

[fatemeh]

Hello all,

i am applying proc mixed with sp(power)covariance structure of random errors .there is only fixed effects and random errors.

what is exactly sp(pow) of cov parm in covariance estimate output table   ? I attached the table bellow. Thanks for any help.

[StatsMan]

This section of the PROC MIXED documentation should help.  Scroll down to table 79.18 under the TYPE= option.  The syntax

    type=sp(pow)(x);

will return two covariance parameters.  The residual variance in your table is the sigma term in the documentation.  The SP(POW) entry in the table is the rho in the documentation.  The Dij is the distance between two observations in terms of the variables you list in parentheses after the SP(POW) ... the X in the statement above.