1
JEE Main 2022 (Online) 28th June Evening Shift
Numerical
+4
-1

Suppose a class has 7 students. The average marks of these students in the mathematics examination is 62, and their variance is 20. A student fails in the examination if he/she gets less than 50 marks, then in worst case, the number of students can fail is _________.

2
JEE Main 2022 (Online) 28th June Morning Shift
Numerical
+4
-1

The mean and standard deviation of 15 observations are found to be 8 and 3 respectively. On rechecking it was found that, in the observations, 20 was misread as 5. Then, the correct variance is equal to _____________.

3
JEE Main 2022 (Online) 25th June Evening Shift
Numerical
+4
-1

If the mean deviation about the mean of the numbers 1, 2, 3, .........., n, where n is odd, is $${{5(n + 1)} \over n}$$, then n is equal to ______________.

4
JEE Main 2021 (Online) 1st September Evening Shift
Numerical
+4
-1
Let X be a random variable with distribution.

x $$-$$2 $$-$$1 3 4 6
P(X = x) $${1 \over 5}$$ a $${1 \over 3}$$ $${1 \over 5}$$ b

If the mean of X is 2.3 and variance of X is $$\sigma$$2, then 100 $$\sigma$$2 is equal to :
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