 M 
Mean, Arithmetic
The measure of central location commonly called the average. It is calculated by adding together all the individual values in a group of measurements and dividing by the number of values in the group.
Mean, Geometric
The mean or average of a set of data measured on a logarithmic scale.
Measure Of Association
A quantified relationship between exposure and disease; includes relative risk, rate ratio, odds ratio.
Measure Of Central Location
A central value that best represents a distribution of data. Measures of central location include the mean, median, and mode.
Measure Of Dispersion
A measure of the spread of a distribution out from its central value. Measures of dispersion used in epidemiology include the interquartile range, variance, and the standard deviation.
Median
The measure of central location which divides a set of data into two equal parts.
Medical Surveillance
The monitoring of potentially exposed individuals to detect early symptoms of disease.
Midrange
The halfway point or midpoint in a set of observations. For most types of data, it is calculated as the sum of the smallest observation and the largest observation, divided by two.
Mode
A measure of central location, the most frequently occurring value in a set of observations.
Morbidity
Any departure, subjective or objective, from a state of physiological or psychological wellbeing.
Mortality Rate
A measure of the frequency of occurrence of death in a defined population during a specified interval of time.
Mortality Rate, Infant
A ratio expressing the number of deaths among children under one year of age reported during a given time period divided by the number of births reported during the same time period. The infant mortality rate is usually expressed per 1,000 live births.
Mortality Rate, Neonatal
A ratio expressing the number of deaths among children from birth up to but not including 28 days of age divided by the number of live births reported during the same time period. The neonatal mortality rate is usually expressed per 1,000 live births.
Mortality Rate, Postneonatal
A ratio expressing the number of deaths among children from 28 days up to but not including 1 year of age during a given time period divided by the number of lives births reported during the same time period. The postneonatal mortality rate is usually exp
