In the U.S., doctors usually get suspicious when a PSA level is 4.0 ng/mL. But studies show that many men with levels well above 4.0 ng/mL do not have cancer. And many men with prostate cancer have PSA scores well below this level. There are a lot of ways to tweak the PSA test to try to get better results.
The Standard Deviation Formula. In this formula, x is the value of the mean, N is the sample size, and x i represents each data value from i=1 to i=N.. The â symbol indicates that you must add up the sum. (x 1 - x) 2 + (x 2 - x) 2 + (x 3 - x) 2 + (x 4 - x) 2 + (x 5 - x) 2. . . + (x N-x) 2.
1 (IQR = Q3-Q1) Quartile deviation or Semi-interquartile range is one-half the difference between the first and the third quartiles. ( 2 QD = Q3-Q1/2) Getting the Quartile Deviation from Ungrouped Data In getting the quartile deviation from ungrouped data, the following steps are used in getting the quartiles: 3  2. 1.uartile Deviation. 1  1. 2  Christian S. Gle BEEd 3rd â A QUARTILE DEVIATION Objectives: To present the procedures in getting the quartile deviation from ungrouped and grouped data. 3  Subject Matter: Topic: Reference: Materials: Methodology: Measures of Variability-Quartile Deviation Educational Measurement and Evaluation pp.