Health care focused variables

Patients with visual acuity problems are either short-sighted or long-sighted. Other cases are eye color where a patient can have blue, brown, red, or green eyes. Blood group is also a nominal variable where one is blood group A, B, AB, or O. According to Velleman and Wilkinson (2013), ordinal variables are categorical variables where the values have some order and a scale. The amount of pain a patient experience is an ordinal variable. An example is the temperature of a patient where there is a difference between valuables like ten degrees as a difference between forty and thirty degrees. Zero degrees, however, does not mean the absence of temperature. Another example is the ph where zero ph implies molarity of one.