5 students of a class have an average height 150 cm and variance $18{\rm{ }}c{m^2}.$ A new student, whose height is 156 cm, joined them. The variance (in $c{m^2}$ )of the height of these six students is

JEE MATHEMATICS MCQ: STATISTICS

1 Easy

1 of 1

Application +4 | -1

5 students of a class have an average height 150 cm and variance

18\mathrm{ }c{m^2}.

A new student, whose height is 156 cm, joined them. The variance (in

c{m^2}

)of the height of these six students is

View answer and explanation

Correct option: C

Option C (20) is correct because it is the variance of the heights of the six students after adding the new student, calculated using the updated mean and the given information.

More Questions from STATISTICS

Practice All Chapter MCQs →

If the mean of a set of observations

{x_1},{x_2}, \ldots ,{x_n}

\bar X,

then the mean of the observations

{x_i} + 2\;i;i = 1,\;2, \ldots ,n

is The sum of 10 items is 12 and sum of their squares is 18 , then standard deviation will be In a family, there are 8 men, 7 women and 5 children whose mean ages separately are respectively 24,20 and 6 years. The mean age of the family is The mean and variance of seven observations are 8 and 16, respectively. If 5 of the observations are 2, 4, 10, 12, 14, then the product of the remaining two observations is

1,3,5, x, y

are 5 observations. Mean of these observations is 5 and variance is 8. Sum of the cubes of the two missing number equals: If s.d. of a set of observations is 8 and if each observation is divided by

-2,

the s.d. of the new set of observations will be