Define mean score m = 70, standard deviation "\\sigma=6", score obtained by a student x.
Probability "P(a<x<b)=P(\\frac{a-m}{\\sigma}<z<\\frac{b-m}{\\sigma})", where z has standard normal distribution.
"P(82<x<\\infty)=P(\\frac{82-70}{6}<z<\\infty)=\\\\\nP(2<z<\\infty)=1-P(z\\leq2)=1-0.9772=0.0228"
"P(64<x<72)=P(\\frac{64-70}{6}<z<\\frac{72-70}{6})=\\\\\nP(-1<z<1\/3)=P(z< 1\/3)-P(z\\leq-1)=\\\\\n0.6306-0.1587=0.4719"
"P(-\\infty<x<50)=P(-\\infty<z<\\frac{50-70}{6})=\\\\\nP(-\\infty<z<-20\/6)=0.0004"
Answer: P(x > 82) = 0.0228, P(64 < x <72) = 0.4719, P(x < 50) = 0.0004.
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