If k∫1(2x−3)dx=12, then k=____
The ratio in which the line segment PQ, where P (-5, 2) and Q (2, 3), is divided by the y-axis is
For observations x1,x2,x3,..........,xn, if ∑ni=1(xi+1)2=9n and ∑ni=1(xi−1)2=5n., then standard deviation of the data is