If they did not complete all their innings (i.e. some innings they finished not out), this number is an estimate of the unknown average number of runs they score per innings.
प्रायः सभी को जब कुछ पूछना हुआ मगर पूछ न सके तो स्वंय ही ऐसी बातें छेड़ देते कि वह बात भी हल हो जाती।