Another variable of interest in the study by Reiss et al. (A-3) (see Exercise 9.3.4) was partial thromboplastin (aPTT), the standard test used to monitor heparin anticoagulation. Use the data in the following table to examine the correlation between aPTT levels as measured by the CoaguCheck point-of-care assay and standard laboratory hospital assay in 90 subjects receiving heparin alone, heparin with warfarin, and warfarin and exoenoxaparin. The name of the datasets are EXR_C09_S07_02 in the form of csv, Excel or sas data.

The datasets can also be download from the website:

http://bcs.wiley.com/he-bcs/Books?&&&

(a) Prepare a scatter diagram.

(b) Compute the sample correlation coefficient.

(c) Test H₀ : at the .05 level of significance and state your conclusions.

(d) Determine the p value for the test.

(e) (Required for doctoral students). Test H₀ : .7 at the .05 level of significance and state your conclusions. Construct the 95 percent confidence interval for r.