Q1. For a normal distribution curve with a mean of 19 and a standard deviation of 6, which range of the variable defines an area under the curve corresponding to a probability of approximately 68%? Ans Normal Distribution Mean ( u ) =19 Standard Deviation ( sd )=6 Normal Distribution = Z= X- u / sd ~ N(0,1) To find P(a < = Z < = b) = F(b) - F(a) P(X < 13) = (13-19)/6 = -6/6 = -1 = P ( Z <-1) From Standard Normal Table = 0.15866 P(X < 25) = (25-19)/6 = 6/6 = 1 = P ( Z <1) From Standard Normal Table = 0.84134 P(13 < X < 25) = 0.84134-0.15866 = 0.6827 ~ 68% Q2. What is the ...
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