5 students of a class have an average height 150 cm and variance 18 cm2. A new student, whose height is 156 cm, joined them. The variance (in cm2) of the height of these six students is
(1) 16
(2) 22
(3) 18
(4) 20
Correct option (4) 20
Explanation:
Let '5' students are x1, x2, x3, x4, x5