Aggregate. Returns values that represent the statistical validity of a regression model.
regr_syy ( dependent-expression , independent-expression )
| dependent-expression | The variable that is affected by the independent variable. The expression accepts numeric datatypes, except timestamp, bigdatetime, and interval. | 
| independent-expression | The variable that influences the outcome. The expression accepts numeric datatypes, except timestamp, bigdatetime, and interval. | 
regr_count( x, y ) * var_pop( y )