The article "Quantitative Estimation of Clay Mineralogy in

Chapter 12, Problem 62E

(choose chapter or problem)

The article "Quantitative Estimation of Clay Mineralogy in Fine-Grains Soils" (J. of Geotechnical and Geoenvironmental Engr., 2011: 997-1008) reported on various chemical properties of natural and artificial soils. Hem are observations on x = cation exchange capacity (CEC, in m2/100 g) and y = specific surface area (SSA, in m2/g) of 20 natural soils.

Minitab gave the: following output in response to a request for r:

correlation of x and y = 0.853

Normal probability plots of x and y are quite straight

a. Carry out a test of hypotheses to see if there is a positive linear association in the population from which the sample data was selected.

b. With n = 20, how small would the value of r have to be in order for the null hypothesis in the test of (a) to not be rejected at significance level .01?

c. Calculate a confidence interval for p using a 95% confidence level.