466 The temperature T in this thermostatically controlled le

4.6.6 The temperature T in this thermostatically controlled lecture hall is a Gaussian random variable with expected value Mu = 68 degrees Fahrenheit. In addition, P[T

Solution

P(T<66) = 0.1587

--> P((T-mean)/s <(66-68)/s) = 0.1587

--> P(Z<-2/s) =0.1587

--> -2/s =-0.9998 (from standard normal table)

So s= 2/0.9998=2.0004

So the variance = 2.0004^2 =4.0016