Assuming the distribution to be normal indicate how many branches have sales between 1. Rs. 90 thousands and Rs 115 thoudands
Given μ=120 thousands,σ=15 thousands
P(90<X<115)=P(X<115)−P(X≤90)
=P(Z<15115−120)−P(Z≤1590−120)
≈P(Z<−0.3333)−P(Z≤−2)
≈0.36944−0.02275≈0.3467
0.3467(700)=243 243 branches have sales between Rs.90,000 and Rs.115,000.
2. Rs. 110 thousands and Rs 135 thoudands
Given μ=120 thousands,σ=15 thousands
P(110<X<135)=P(X<135)−P(X≤110)
=P(Z<15135−120)−P(Z≤15110−120)
≈P(Z<1)−P(Z≤−0.6667)
≈0.84134−0.25249≈0.5889
0.5889(700)=412 412 branches have sales between Rs.110,000 and Rs.135,000.
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