The mean and variance of 8 observations are 10 and 13.5, respectively. If 6 of these observations are 5, 7, 10, 12, 14, 15, then the absolute difference between the remaining two observations is :

Suppose that the other two numbers are a,bGiven the mean of 8 observations is 105+7+10+12+14+15+a+b8=1063+a+b=80a+b=17The variance of 8 observations is 13.5           Hence, 25+49+100+144+225+196+a2+b2−8008=13.5739+a2+b2−8008=13.5a2+b2=169 Frome the above equations, will get (a-b)2=49, it implies a-b=7