In an experiment to determine the factors affecting tensile strength in steel plates, the tensile strength (in kg/mm2), the manganese content (in parts per thousand), and the thickness (in mm) were measured for a sample of 20 plates. The following MINITAB output presents the results of fitting the model Tensile strength = β0+ β1 Manganese + β2Thickness.
a. Predict the strength for a specimen that is 10 mm thick and contains 8.2 ppt manganese.
b. If two specimens have the same thickness, and one contains 10 ppt more manganese, by how much would you predict their strengths to differ?
c. If two specimens have the same proportion of manganese, and one is 5 mm thicker than the other, by how much would you predict their strengths to differ?
Chapter 8: bivariate correlational research - When you see two things that are related, and you think are related, but actually have nothing to do with one another To be causal - Covariance - Internal validity - Temporal precedence Correlational strength - As you get a measurement change by this much on this chart or whatever - You get the same...