If the mean of sample data 1, 2, 3 and 2 is a, the median is B, and the mode is C, then the variance of data a, B and C is a______ .

If the mean of sample data 1, 2, 3 and 2 is a, the median is B, and the mode is C, then the variance of data a, B and C is a______ .

The mean a = (1 + 2 + 3 + 2) △ 4 = 2; median B = (2 + 2) △ 2 = 2; mode C = 2; variance of a, B, C = [(2-2) 2 + (2-2) 2 + (2-2) 2] △ 3 = 0