Question

Assume that the readings at freezing on a bundle of thermometers are normally distributed with a mean of 0°C and a standard deviation of 1.00°C. A single thermometer is randomly selected and tested. Find the probability of obtaining a reading less than -1.503°C.

P(Z<−1.503)=P(Z<-1.503)=

Answer 1

P(Y < -1.503) = P(Y - mean < -1.503 - mean)
                  = P( (Y - mean)/SD < (-1.503 - mean)/SD
                  = P(Z < (-1.503 - mean)/SD)
                  = P(Z < (-1.503 - 0)/1)
                  = P(Z < -1.503)
                  = 0.066