The mean of the numbers a, b,8,5 and 10 is 6 and the variance is 6.80. Then, which one of the following gives possible values of a and b?
a=3,b=4
a=0,b=7
a=5,b=2
a=1,b=6
According to the given condition,
6.80=(6−a)2+(6−b)2+(6−8)2+(6−5)2+(6−10)25⇒ 34=(6−a)2+(6−b)2+4+1+16⇒ (6−a)2+(6−b)2=13=9+4⇒ (6−a)2+(6−b)2=32+22⇒ a=3,b=4