1
JEE Main 2020 (Online) 5th September Evening Slot
+4
-1
If the mean and the standard deviation of the
data 3, 5, 7, a, b are 5 and 2 respectively, then a and b are the roots of the equation :
A
x2 – 20x + 18 = 0
B
2x2 – 20x + 19 = 0
C
x2 – 10x + 18 = 0
D
x2 – 10x + 19 = 0
2
JEE Main 2020 (Online) 5th September Morning Slot
+4
-1
The mean and variance of 7 observations are 8 and 16, respectively. If five observations are 2, 4, 10, 12, 14, then the absolute difference of the remaining two observations is:
A
2
B
3
C
1
D
4
3
JEE Main 2020 (Online) 4th September Morning Slot
+4
-1
The mean and variance of 8 observations are 10 and 13.5, respectively. If 6 of these observations are 5, 7, 10, 12, 14, 15, then the absolute difference of the remaining two observations is :
A
5
B
3
C
7
D
9
4
JEE Main 2020 (Online) 3rd September Evening Slot
+4
-1
Let xi (1 $$\le$$ i $$\le$$ 10) be ten observations of a random variable X. If
$$\sum\limits_{i = 1}^{10} {\left( {{x_i} - p} \right)} = 3$$ and $$\sum\limits_{i = 1}^{10} {{{\left( {{x_i} - p} \right)}^2}} = 9$$
where 0 $$\ne$$ p $$\in$$ R, then the standard deviation of these observations is :
A
$${7 \over {10}}$$
B
$${9 \over {10}}$$
C
$${4 \over 5}$$
D
$$\sqrt {{3 \over 5}}$$
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