Let a, b, c, d, e be 5 unknown observations.n = 7, Mean = 8, Variance = 16∴ sum of observations =7×8=56 ​⇒ Mean of 5 remaining observations =556−8−6​=542​16=7∑xi2​​−64⇒Σxi2​=560⇒a2+b2+c2+d2+e2+64+36=560⇒a2+b2+c2+d2+e2=460​ ∴ Variance of remaining 5 observations =5460​−(542​)2=25536​