The mean of five observations is 4 and their variance is 5.2 . If three of these observations are 1, 2 and 6, then the other two observations are

Let 'P' be the mean deviation of the first five odd natural numbers about their mean and 'Q' be the mean deviation of the first five prime numbers about their mean. The $$Q-P=$$

The mean of the numbers $$a, b, 8,5,10$$ is 6 and the variance is 6.80 , then which of the following gives possible values of $$a$$ & $$b$$

Consider the first 10 natural numbers. If we multiply each number by $$-$$1 and add 1 to each number, the variance of the numbers so obtained is