Reference no: EM132907204

Urinary angiotensinogen (AGT) level is one quantitative indicator of kidney function. The article "Urinary Angiotensinogen as a Potential Biomarker of Chronic Kidney Diseases" (J. of the Amer. Society of Hypertension, 2008: 349-354) describes a study in which urinary AGT level (mg) was determined for a sample of adults with chronic kidney disease. Here is representative data (consistent with summary quantities and descriptions in the cited article): 2.6 6.2 7.4 9.6 11.5 13.5 14.5 17.0 20.0 28.8 29.5 29.5 41.7 45.7 56.2 56.2 66.1 66.1 67.6 74.1 97.7 141.3 147.9 177.8 186.2 186.2 190.6 208.9 229.1 229.1 288.4 288.4 346.7 407.4 426.6 575.4 616.6 724.4 812.8 1122.0 An appropriate probability plot supports the use of the lognormal distribution (see Section 4.5) as a reasonable model for urinary AGT level (this is what the investigators did).

a. Estimate the parameters of the distribution. [Hint: Reme mber that X has a lognormal distribution with parameters m and s2 if ln(X) is normally distributed with mean m and variance s2.]

b. Use the estimates of part (a) to calculate an estimate of the expected value of AGT level. [Hint: What is E(X)?]