17. A regression of y
calcium content (g/L) on x
dissolved material (mg/cm2

) was reported in the article “Use of Fly Ash or Silica Fume to Increase the Resistance of Concrete to Feed Acids” (Magazine of Concrete Research, 1997: 337–344).

The equation of the estimated regression line was y

3.678 .144x, with r 2
.860, based on n
23.

a. Interpret the estimated slope .144 and the coefficient of determination .860.

b. Calculate a point estimate of the true average calcium content when the amount of dissolved material is 50 mg/cm2

.

c. The value of total sum of squares was SST
320.398.

Calculate an estimate of the error standard deviation in the simple linear regression model.