1.m/1+m/2+m/3+m/4=1 m=12/25
2.X的分布列
Xx051x05 2x05 3x05 4
Px050.48x050.24x050.16x050.12
3.
EX=1*0.48+2*0.24+3*0.16+4*0.12=1.92
1.m/1+m/2+m/3+m/4=1 m=12/25
2.X的分布列
Xx051x05 2x05 3x05 4
Px050.48x050.24x050.16x050.12
3.
EX=1*0.48+2*0.24+3*0.16+4*0.12=1.92