1
JEE Main 2021 (Online) 27th August Evening Shift
Numerical
+4
-1
An online exam is attempted by 50 candidates out of which 20 are boys. The average marks obtained by boys is 12 with a variance 2. The variance of marks obtained by 30 girls is also 2. The average marks of all 50 candidates is 15. If $$\mu$$ is the average marks of girls and $$\sigma$$2 is the variance of marks of 50 candidates, then $$\mu$$ + $$\sigma$$2 is equal to ________________.
2
JEE Main 2021 (Online) 27th August Morning Shift
Numerical
+4
-1
Let n be an odd natural number such that the variance of 1, 2, 3, 4, ......, n is 14. Then n is equal to _____________.
3
JEE Main 2021 (Online) 26th August Evening Shift
Numerical
+4
-1
Let the mean and variance of four numbers 3, 7, x and y(x > y) be 5 and 10 respectively. Then the mean of four numbers 3 + 2x, 7 + 2y, x + y and x $$-$$ y is ______________.
4
JEE Main 2021 (Online) 25th July Morning Shift
Numerical
+4
-1
Consider the following frequency distribution :

Class : 10-20 20-30 30-40 40-50 50-60
Frequency : $$\alpha$$ 110 54 30 $$\beta$$

If the sum of all frequencies is 584 and median is 45, then | $$\alpha$$ $$-$$ $$\beta$$ | is equal to _______________.