private function buildMean(Dataset $dataset): self
    {
        $this->mean = mean(...$dataset->ordinates());

        return $this;
    }
private function buildMean(Dataset $dataset): self
    {
        $this->mean = mean(...$dataset->ordinates());

        return $this;
    }
private function buildMean ( Dataset $ dataset ) : self { $ this -> mean = mean ( ... $ dataset -> ordinates ( ) ) ; return $ this ; }
Build the mean value from the dataset

@param Dataset $dataset

@return self
Build the mean value from the dataset