Improved doctest coverage for sympy.statistics.
Improved doctest coverage for sympy.statistics.

Added Doctests for all functions in sympy.statistics module.

ahhda/sympy,Sumith1896/sympy,kevalds51/sympy,sahmed95/sympy,beni55/sympy,kumarkrishna/sympy,skidzo/sympy,skirpichev/omg,Gadal/sympy,kaichogami/sympy,jbbskinny/sympy,mafiya69/sympy,pbrady/sympy,jaimahajan1997/sympy,rahuldan/sympy,meghana1995/sympy,dqnykamp/sympy,chaffra/sympy,Designist/sympy,sahmed95/sympy,jerli/sympy,MridulS/sympy,atsao72/sympy,Designist/sympy,sahilshekhawat/sympy,AunShiLord/sympy,lidavidm/sympy,kevalds51/sympy,rahuldan/sympy,Davidjohnwilson/sympy,moble/sympy,oliverlee/sympy,Arafatk/sympy,wanglongqi/sympy,wanglongqi/sympy,chaffra/sympy,Shaswat27/sympy,souravsingh/sympy,Curious72/sympy,lindsayad/sympy,cccfran/sympy,lindsayad/sympy,Gadal/sympy,jaimahajan1997/sympy,abloomston/sympy,cswiercz/sympy,aktech/sympy,Arafatk/sympy,mafiya69/sympy,ga7g08/sympy,kmacinnis/sympy,farhaanbukhsh/sympy,beni55/sympy,flacjacket/sympy,sahmed95/sympy,kumarkrishna/sympy,shipci/sympy,yashsharan/sympy,kmacinnis/sympy,sunny94/temp,iamutkarshtiwari/sympy,AunShiLord/sympy,maniteja123/sympy,yukoba/sympy,emon10005/sympy,lindsayad/sympy,toolforger/sympy,Curious72/sympy,abhiii5459/sympy,atreyv/sympy,vipulroxx/sympy,sampadsaha5/sympy,oliverlee/sympy,asm666/sympy,moble/sympy,abhiii5459/sympy,garvitr/sympy,atsao72/sympy,sampadsaha5/sympy,Vishluck/sympy,ahhda/sympy,AunShiLord/sympy,shikil/sympy,yukoba/sympy,kaushik94/sympy,ChristinaZografou/sympy,bukzor/sympy,moble/sympy,grevutiu-gabriel/sympy,yashsharan/sympy,debugger22/sympy,emon10005/sympy,farhaanbukhsh/sympy,kumarkrishna/sympy,saurabhjn76/sympy,mcdaniel67/sympy,MridulS/sympy,toolforger/sympy,aktech/sympy,atsao72/sympy,garvitr/sympy,liangjiaxing/sympy,jbbskinny/sympy,atreyv/sympy,Arafatk/sympy,shikil/sympy,kevalds51/sympy,postvakje/sympy,pandeyadarsh/sympy,VaibhavAgarwalVA/sympy,wyom/sympy,cccfran/sympy,emon10005/sympy,ga7g08/sympy,ChristinaZografou/sympy,asm666/sympy,hargup/sympy,Mitchkoens/sympy,Vishluck/sympy,grevutiu-gabriel/sympy,AkademieOlympia/sympy,yukoba/sympy,Shaswat27/sympy,mcdaniel67/sympy,maniteja123/sympy,cccfran/sympy,cswiercz/sympy,pandeyadarsh/sympy,saurabhjn76/sympy,Curious72/sympy,sahilshekhawat/sympy,jamesblunt/sympy,maniteja123/sympy,hrashk/sympy,bukzor/sympy,MechCoder/sympy,meghana1995/sympy,MridulS/sympy,rahuldan/sympy,Sumith1896/sympy,Titan-C/sympy,ga7g08/sympy,shipci/sympy,hargup/sympy,cswiercz/sympy,saurabhjn76/sympy,debugger22/sympy,pandeyadarsh/sympy,hargup/sympy,lidavidm/sympy,ChristinaZografou/sympy,abhiii5459/sympy,beni55/sympy,mafiya69/sympy,debugger22/sympy,jbbskinny/sympy,bukzor/sympy,vipulroxx/sympy,drufat/sympy,drufat/sympy,MechCoder/sympy,VaibhavAgarwalVA/sympy,kmacinnis/sympy,Vishluck/sympy,iamutkarshtiwari/sympy,Gadal/sympy,madan96/sympy,srjoglekar246/sympy,Mitchkoens/sympy,meghana1995/sympy,dqnykamp/sympy,lidavidm/sympy,chaffra/sympy,sunny94/temp,wyom/sympy,souravsingh/sympy,sahilshekhawat/sympy,postvakje/sympy,Mitchkoens/sympy,farhaanbukhsh/sympy,aktech/sympy,garvitr/sympy,Titan-C/sympy,grevutiu-gabriel/sympy,amitjamadagni/sympy,souravsingh/sympy,abloomston/sympy,AkademieOlympia/sympy,liangjiaxing/sympy,liangjiaxing/sympy,oliverlee/sympy,drufat/sympy,jamesblunt/sympy,abloomston/sympy,jaimahajan1997/sympy,pbrady/sympy,madan96/sympy,skidzo/sympy,hrashk/sympy,asm666/sympy,pbrady/sympy,Designist/sympy,dqnykamp/sympy,Shaswat27/sympy,sunny94/temp,shipci/sympy,hrashk/sympy,toolforger/sympy,Davidjohnwilson/sympy,jerli/sympy,kaichogami/sympy,vipulroxx/sympy,MechCoder/sympy,wanglongqi/sympy,diofant/diofant,jerli/sympy,kaushik94/sympy,mcdaniel67/sympy,atreyv/sympy,amitjamadagni/sympy,Davidjohnwilson/sympy,kaichogami/sympy,kaushik94/sympy,wyom/sympy,iamutkarshtiwari/sympy,sampadsaha5/sympy,madan96/sympy,postvakje/sympy,ahhda/sympy,yashsharan/sympy,Titan-C/sympy,skidzo/sympy,VaibhavAgarwalVA/sympy,jamesblunt/sympy,Sumith1896/sympy,AkademieOlympia/sympy,shikil/sympy