Hydrogen content is conjectured to be an important factor in porosity of aluminum alloy...

Hydrogen content is conjectured to be an important factor in porosity of aluminum alloy castings. The article “The Reduced Pressure Test as a Measuring Tool in the Evaluation of Porosity/Hydrogen Content in A1–7 Wt Pct Si-10 Vol Pct SiC(p) Metal Matrix Composite” (Metallurgical Trans., 1993: 1857–1868) gives the accompanying data on x content and y gas porosity for one particular measurement technique.

Minitab gives the following output in response to a Correlation command:

a. Test at level .05 to see whether the population correlation coefficient differs from 0.

b. If a simple linear regression analysis had been carried out, what percentage of observed variation in porosity could be attributed to the model relationship?