1
JEE Main 2023 (Online) 25th January Morning Shift
+4
-1

The mean and variance of the marks obtained by the students in a test are 10 and 4 respectively. Later, the marks of one of the students is increased from 8 to 12. If the new mean of the marks is 10.2, then their new variance is equal to :

A
3.92
B
4.08
C
3.96
D
4.04
2
JEE Main 2023 (Online) 24th January Evening Shift
+4
-1

Let the six numbers $$\mathrm{a_1,a_2,a_3,a_4,a_5,a_6}$$, be in A.P. and $$\mathrm{a_1+a_3=10}$$. If the mean of these six numbers is $$\frac{19}{2}$$ and their variance is $$\sigma^2$$, then 8$$\sigma^2$$ is equal to :

A
220
B
210
C
105
D
200
3
JEE Main 2022 (Online) 25th July Evening Shift
+4
-1

If the mean deviation about median for the numbers 3, 5, 7, 2k, 12, 16, 21, 24, arranged in the ascending order, is 6 then the median is :

A
11.5
B
10.5
C
12
D
11
4
JEE Main 2022 (Online) 29th June Evening Shift
+4
-1

The number of values of a $$\in$$ N such that the variance of 3, 7, 12, a, 43 $$-$$ a is a natural number is :

A
0
B
2
C
5
D
infinite
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