Question

The spending at Target is distributed normally with a mean spending of $45.67 and a standard deviation of $5.50. What is the probability that the spending is less than $51?

Answer 1

P(Y < 51) = P(Y - mean < 51 - mean)
                  = P( (Y - mean)/SD < (51 - mean)/SD
                  = P(Z < (51 - mean)/SD)
                  = P(Z < (51 - 45.67)/5.5)
                  = P(Z < 0.969)
                  = 0.834----------from standard normal table.