The time x a student spends learning a computer software pac

The time x a student spends learning a computer software package is normally distributed with a mean of 8 hours and a standard deviation of 1.5 hours. A student is selected at random. What is the probability that the student spends less than 6 hours learning the software package?

Solution

P(X<6)=P(((X-mean)/(std deviation))<((6-8)/1.5) = P(Z<-1.34)

which can be found from normal table as 0.5 - 0.4099 = .0901

i.e 9.01 perctentage of chance