1st order the data point from smaller to greater:
x = 25,31,46,52,55,67 (n=number of data points = 6)
2nd Add them up = 25+31+46+52+55+67 = 276
3rd : find the mean 276/5 = 46 = mean
4th make (x- mean)² for each x. EXAMPLE:
25-46 = -21 →→(-21)² = 441
31-46 = -15→→(-15)² = 225
AND SO ON AND SO FORTH. Then add all squared together you will get:
∑(x-mean)² = 1224
variance = ∑(x-mean)²/(n-1) = 1224-5 = 1219