Solved: No-fines concrete, made from a uniformly graded coarseaggregate and a

Chapter 12, Problem 17

(choose chapter or problem)

No-fines concrete, made from a uniformly graded coarseaggregate and a cement-water paste, is beneficial in areasprone to excessive rainfall because of its excellent drainageproperties. The article Pavement Thickness Design for No-Fines Concrete Parking Lots, J. of Trans. Engr., 1995:476484) employed a least squares analysis in studying howporosity (%) is related to unit weight (pcf) in concretespecimens. Consider the following representative data:x 99.0 101.1 102.7 103.0 105.4 107.0 108.7 110.8y 28.8 27.9 27.0 25.2 22.8 21.5 20.9 19.6x 112.1 112.4 113.6 113.8 115.1 115.4 120.0y 17.1 18.9 16.0 16.7 13.0 13.6 10.8Relevant summary quantities area. Obtain the equation of the estimated regression line.Then create a scatter plot of the data and graph theestimated line. Does it appear that the model relationshipwill explain a great deal of the observed variation in y?b. Interpret the slope of the least squares line.c. What happens if the estimated line is used to predictporosity when unit weight is 135? Why is this not a goodidea?d. Calculate the residuals corresponding to the first twoobservations.e. Calculate and interpret a point estimate of s.f. What proportion of observed variation in porosity can beattributed to the approximate linear relationship betweenunit weight and porosity?