Let the mean and standard deviation of marks of class A of 100 students be respectively 40 and α(> 0), and the mean and standard deviation of marks of class B of n students be respectively 55 and 30 -α. If the mean and variance of the marks of the combined class of 100+n studants are respectively 50 and 350, then the sum of variances of classes A and B is:

Statistics and Probability: JEE Main 2023 Mathematics question

JEE Main 2023 · 31 Jan, Evening shift · Q5477

JEE Main 202331 Jan, Evening shiftMathematicsHardStatistics and Probability258× since 2002

Let the mean and standard deviation of marks of class A of 100 students be respectively 40 and

\alpha(>

0 ), and the mean and standard deviation of marks of class

B

n

students be respectively 55 and 30

-\alpha

. If the mean and variance of the marks of the combined class of

100+\mathrm{n}

studants are respectively 50 and 350 , then the sum of variances of classes

A

and

B

is :

JEE Main 2023 Statistics and Probability Question with Solution (31 Jan Evening shift, Q5477) | JEE Arc