The length, X, in minutes of a MS Teams video lecture for STBE101 is normally distributed
with a mean of 28 minutes and standard deviation of 2 minutes.
(a) Find ππ(20 < ππ < 28)
(b) Find ππ(ππ > 33)
(a)
"=P(Z<\\dfrac{28-\\mu}{\\sigma})-P(Z\\leq \\dfrac{20-\\mu}{\\sigma})"
"=P(Z<\\dfrac{28-28}{2})-P(Z\\leq \\dfrac{20-28}{2})"
"=P(Z<0)-P(Z\\leq -4)"
"=0.5-0.00003167"
"=0.49996833"
(b)
"=1-P(Z\\leq \\dfrac{33-\\mu}{\\sigma})"
"=1-P(Z\\leq \\dfrac{33-28}{2})"
"=1-P(Z\\leq2.5)"
"=0.00620967"
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