P(x≤4)=P[(x-2)/σ≤2/σ]=0.84
P(x≤0)=P[(x-2)/σ≤-2/σ]=P[(x-2)/σ≥2/σ]= P[(x-2)/σ>2/σ]=1-P[(x-2)/σ≤2/σ]=1-0.84=0.16