m1=3
f甲胜=2/3*2/3*2/3=8/27=0.296 f乙胜=1/3*1/3*1/3=1/27=0.037
f1=f甲 +f乙=0.296+0.037=0.333
m2=4
f甲胜=2/3*2/3*2/3*1/3*3=24/81=0.296 f乙胜=1/3*1/3*1/3*2/3*3=6/81=0.074
f2=f甲 +f乙=0.296+0.074=0.370
m3=5
f甲胜=2/3*2/3*2/3*1/3*1/3*6=48/243=0.198 f乙胜=1/3*1/3*1/3*2/3*2/3*6=24/243=0.099
f3=f甲 +f乙=0.198+0.099=0.297
m的数学期望值=m1*f1+m2*f2+m3*f3=3*0.333+4*0.370+5*0.297=3.964