1. n(n-1)/2
2. n(n-1)(n-2)/6
3. n(n-1)
4. n(n-3)/2
n(n-3)/2
1. 27
2. 256
3. 29
4. 258
256
1. T12=T13
2. x2-T13= T12
3. T12=x2T13
4. T12+T13=25
x<sup>2</sup>-T<sub>13</sub>= T<sub>12</sub>
1. 6
2. 9
3. 69
4. 96
69
1. α+β
2. α-β
3. αβ
4. 2α-β
α-β
1. (81/25, 92/25)
2. (92/25, 81/25)
3. (46/25, 54/25)
4. (-81/25, 92/25)
(81/25, 92/25)
1. 2
2. 4
3. 1
4. 3
4
1. 3/4
2. 1/4
3. 1/2
4. 1/3
1/4
1. λ=1/2σ2
2. σ2=1/2λ
3. λ=σ2
4. σ2=λ2
λ=σ<sup>2</sup>
1. 5
2. 10
3. 15
4. 20
10