Risastatisticalcomputerprogram,madeavailablethroughtheInternetundertheGeneralPublicLicense(GPL).Thatis,itissuppliedwithalicensethatallowsyoutouseitfreely,distributeit,orevensellit,aslongasthereceiverhasthesamerightsandthesourcecodeisfreelyavailable.ItexistsforMicrosoftWindows