std 20,16 3/4 ,13 1/2 ,10 1/4 ,7

解答

标准差

20, 16 \frac{3}{4}, 13 \frac{1}{2}, 10 \frac{1}{4}, 7

6.72123 \dots

求解步骤

计算方差:

45.175

计算

σ (X) = i = 1 \sum n \frac{( x _{i} - x ˉ ) ^{2}}{n - 1} : 6.72123 \dots

6.72123 \dots

C (9, 4)

m e d ian 22, 26, 31, 31, 33, 33, 36, 36, 37, 37, 38, 38, 39, 41, 42, 42, 43, 43, 44, 44, 44

26 C 10

7 n P r 7

4 n C r 1