Two pieces of wood need to be glued together. After applying glue to both pieces, they must be clamped to obtain the best results. The required clamping time in any application is a random variable. Find the standardized variable Z, for the clamping time X, when using a manufacturers'
(a) Wood glue which has mean 25 minutes and standard deviation 3 minutes.
(b) General purpose glue which has mean 90 minutes and standard deviation 12 minutes.