想問關於機率分配的問題?

1)
P(0<=Z<=a)=0.475
a=1.96

2)
P(Z>=a)=0.1314
P(0<=Z<=a)=0.3686
a=1.12

3)
P(Z<=a)=0.67
P(a=>Z=>0)=0.17
a=0.44

4)
P(Z<=a)=0.2119
P(a=>Z=>0)=0.2881
a=0.8

5)
P(Z>=a)=0.6915
P(a>=Z>=0)=0.1915
a=0.5

6)
P(-a<=Z<=a)=0.903
2P(0<=Z<=a)=0.903
P(0<=Z<=a)=0.4515
a=1.66

7)
P(-a<=Z<=a)=0.2052
P(0<=Z<=a)=0.1026
a=0.26

查表即可。
Z ~ N(0, 1)

(1)
P(0 ≤ Z ≤ a) = 0.475
P(Z ≤ a) = 0.5 + 0.475 = 0.975
a = 1.96

(2)
P(Z ≥ a) = 0.1314
P(Z < a) = 1 - 0.1314 = 0.8686
P(0 < Z < a) = 0.8686 - 0.5 = 0.3686
a = 1.12

(3)
P(Z ≤ a) = 0.67
P(0 < Z ≤ a) = 0.67 - 0.5 = 0.16
a = 0.44

(4)
P(Z ≤ a) = 0.2119
P(Z > a) = 1 - 0.2119 = 0.7881
P(Z < -a) = 0.7881
P(0 < Z < -a) = 0.7881 - 0.5 = 0.2881
-a = 0.8
a = -0.8

(5)
P(Z ≥ a) = 0.6915
P(Z < -a) = 0.6915
P(0 < Z < -a) = 0.6915 - 0.5 = 0.1915
-a = 0.5
a = -0.5

(6)
P(-a ≤ Z ≤ a) = 0.903
P(0 ≤ Z ≤ a) = 0.903 ÷ 2 = 0.4515
P(Z ≤ a) = 0.5 + 0.4515 = 0.9515
a = 1.66

(7)
P(-a ≤ Z ≤ a) = 0.2052
P(0 ≤ Z ≤ a) = 0.2052 ÷ 2 = 0.1026
P(Z ≤ a) = 0.5 + 0.1026 = 0.6026
a = 0.26