1
JEE Main 2023 (Online) 30th January Evening Shift
+4
-1
Let $S$ be the set of all values of $a_1$ for which the mean deviation about the mean of 100 consecutive positive integers $a_1, a_2, a_3, \ldots ., a_{100}$ is 25 . Then $S$ is :
A
$\{9\}$
B
$\phi$
C
$\{99\}$
D
N
2
JEE Main 2023 (Online) 29th January Morning Shift
+4
-1

Three rotten apples are mixed accidently with seven good apples and four apples are drawn one by one without replacement. Let the random variable X denote the number of rotten apples. If $$\mu$$ and $$\sigma^2$$ represent mean and variance of X, respectively, then $$10(\mu^2+\sigma^2)$$ is equal to :

A
20
B
30
C
250
D
25
3
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
4
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
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