List of top Mathematics Questions on Variance and Standard Deviation asked in KEAM

The variance for the data: $65, 70, 75$ is

The standard deviation of the numbers \( -3, 0, 3, 8 \) is

For two data sets, each of size 5, the variances are given to be 4 and 5 and the corresponding means are given to be 2 and 4, respectively. The variance of the combined data set is

The standard deviation of the data \( 6, 5, 9, 13, 12, 8, 10 \) is

The standard deviation of the data \( 6, 5, 9, 13, 12, 8, 10 \) is

The standard deviation of the data \( 6, 5, 9, 13, 12, 8, 10 \) is

Variance of first 20 natural numbers

The standard deviation of the data \( 6, 5, 9, 13, 12, 8, 10 \) is

Standard deviation of first \( n \) odd natural numbers is:

In an experiment with 15 observations on \( x \), the results \( \sum x^2 = 2830 \) and \( \sum x = 170 \) were available. One observation (20) was wrong and was replaced by 30. The corrected variance is:

If the mean of the numbers $a, b, 8, 5, 10$ is $6$ and their variance is $6.8$, then $ab$ is equal to: