Hello,

I have been testing for the serial correlation using the Woodridge test but i seem to have this error
I am using panel data and have useed the -xtreg command for these

xi xtserial iGDPpercapitagrowth i.RealGDPpercapita i.FDI i.Populationrate
> i.Corruptioncontrolindex i.HDI i.TradeOpenness i.PoliticalStability
i.RealGDPperc~a _IRealGDPpe_1-446 (_IRealGDPpe_1 for Rea~a==500.4228825
> omitted)
i.FDI _IFDI_1-449 (_IFDI_1 for FDI==-6915050000 omitted
> )
i.Populationr~e _IPopulatio_1-450 (_IPopulatio_1 for Pop~e==-.759628600
> 9282213 omitted)
i.Corruptionc~x _ICorruptio_1-450 (_ICorruptio_1 for Cor~x==-1.685389 o
> mitted)
i.HDI _IHDI_1-422 (_IHDI_1 for HDI==.27125 omitted)
i.TradeOpenness _ITradeOpen_1-436 (_ITradeOpen_1 for Tra~s==1.478492272
> 170269 omitted)
i.PoliticalSt~y _IPolitical_1-449 (_IPolitical_1 for Pol~y==-2.7632835
> omitted)