While finding P(X≤82) for Bin(200,0.5) Mean =np = 200*0.5 =100 agreed So in denominator it should be npq= √200*0.5*0.95= √95 In calculation for Z value Why √50 is used here ? Thanks in advance.
You are doing a calculation mistake. Here p = 0.5, hence q = (1-p) = 1-0.5 = 0.5 Therefore variance = npq = 200*0.5*0.5 = 50
