If the mean of a set of observations`x_1`, `x_2`________ `x_10` is 20. Find the mean of `x_1` + 4, `x_2` + 8, `x_3` + 12,_________`x_10`+40.

The mean of the observations x-1, x and x + 1 is

If the mean of x_1, x_2, ....., x_n is barx then the mean of x_1/a,x_2/a, .... x_n/a is .......

The mean of x - 1, x and x + 1 is

Mean of n-observations x_1,x_2 ,……………., x_n repeated f_1, f_2, f_3 ……………. f_n times if……….

Observe the following statements : (A) : 10 is the mean of a set of 7 obervations and 5 is the mean of a set of 3 observations. The mean of a combined set is 9. (R ) : If bar(x)_(i)(i = 1,2,…,k) are the means of k - series n_(i)(I = 1,2,3,…,k) respectively, then the combined or composite mean is bar(x) = (n_(1)bar(x)_(1) + n_(2) bar(x)_(2) + ...+ n_(k)bar(x_(k)))/(n_(1)+n_(2)+...+n_(k))

Consider any set of 201 observation x_(1),x_(2)………..,x_(200),x_(201) . It is given that x_(1) lt x_(2) lt …… lt x_(200) lt x_(201) . Then the mean deviation of this set of observations about a point k is minimum which k equals.

Find the coefficient of x^9 and x^10 in (2x^2 - 1/x)^20