Let n be an odd natural number such that the variance of 1, 2, 3, 4, ......, n is 14. Then n is equal to _____________.

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 ______________.

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 _______________.

Consider the following frequency distribution :

Class :	0-6	6-12	12-18	18-24	24-30
Frequency :	$$a $$	$$b$$	12	9	5

If mean = $${{309} \over {22}}$$ and median = 14, then the value (a $$-$$ b)² is equal to _____________.