1)Giventhat,x1=66,x2=75,Z1=−0.6,Z2=1.1,thenZ=σx−μ∴−0.6=σ66−μ⟹−0.6σ=66−μ,∴1.1=σ75−μ⟹1.1σ=75−μ,by multiplying the first equation by (-1) and then adding the result to the second equation1.7σ=−66+75=9⟹σ=1.79≈5.294,μ=66+0.6(5.294)=69.17642)Giventhat,μ=97.6,σ=10.4,then,a)P(x>100)=P(Z>10.4100−97..6)=P(Z>0.23)=0.5−P(0<Z<0.23)=0.5−0.0910=0.409number of bulbs =1600×0.409=654.4≈655vehicles
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