The research and development team of a medical device manufacturer is designing a new diagnostic test strip to detect the breath alcohol level. The materials are assembled as shown in the following figure.
Production data for each of the four components is summarized in the following table. All measurements are in millimetres.
a. Compute an estimate of the mean and variance of the thickness of assembled strips.
b. Assuming random assembly, what is the probability that the thickness of a strip, selected at random will exceed 75 mm?