The mean deviation of the series `a , a+d , a+2d ,.....,a+2n` from its mean is (a)`((n+1)d)/(2n+1)` (b) `(n d)/(2n+1)` (c) `(n(n+1)d)/(2n+1)` (d) `((2n+1)d)/(n(n+1))`

The mean deviation of the series a , a+d , a+2d , , a+2n from its mean is ((n+1)d)/(2n+1) (b) (n d)/(2n+1) (c) (n(n+1)d)/(2n+1) (d) ((2n+1)d)/(n(n+1))

(d^n)/(dx^n)(logx)=? (a) ((n-1)!)/(x^n) (b) (n !)/(x^n) (c) ((n-2)!)/(x^n) (d) (-1)^(n-1)((n-1)!)/(x^n)

(d^n)/(dx^n)(logx)= ((n-1)!)/(x^n) (b) (n !)/(x^n) ((n-2)!)/(x^n) (d) (-1)^(n-1)((n-1)!)/(x^n)

The arithmetic mean of 1,2,3,...n is (a) (n+1)/2 (b) (n-1)/2 (c) n/2 (d) n/2+1

The arithmetic mean of 1,2,3,...n is (a) (n+1)/2 (b) (n-1)/2 (c) n/2 (d) n/2+1

The algebraic sum of the deviations of a set of n values from their mean is (a) 0 (b) n-1 (c) n (d) n+1

If tanx=ntany ,n in R^+, then the maximum value of sec^2(x-y) is equal to (a) ((n+1)^2)/(2n) (b) ((n+1)^2)/n (c) ((n+1)^2)/2 (d) ((n+1)^2)/(4n)

The standard deviation of the data: x : , 1, a , a^2 , ..., a^n f: , ^n C_0 , ^n C_1 , ^n C_2 , ..., ^n C_n is ((1+a^2)/2)^n-((1+a)/2)^(2n) (b) ((1+a^2)/2)^(2n)-((1+a^2)/2)^(2n) (c) ((1+a)/2)^(2n)-((1+a^2)/2)^n (d) none of these

The mean of n observations is X . If the first item is increased by 1, second by 2 and so on, then the new mean is (a) X +n (b) X +n/2 (c) X +(n+1)/2 (d) None of these

The mean of first n odd natural number is (a) (n+1)/2 (b) n/2 (c) n (d) n^2