# median

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## median

[me´de-an]**1.**situated in the median plane or in the midline of a body or structure.

**2.**any value that divides the probability distribution of a random variable in half; that is, the probability of observing a value above the median and the probability of observing a value below the median are both less than or equal to one-half. For a finite population or sample, the median is the middle value of an odd number of values (arranged in ascending value) or any value between the two middle values of an even number of values; in the latter case it is conventional to use the average of the two middle values.

## me·di·an

(mē'dē-ăn),**1.**middle; lying in the midline. Synonym(s): medianus

**2.**The middle value in a set of measurements; like the mean, a measure of central tendency.

[L.

*medianus,*middle]## median

(mē′dē-ən)*adj.*

**1.**Relating to, located in, or extending toward the middle.

**2.**

*Anatomy*Of, relating to, or situated in or near the plane that divides a bilaterally symmetrical animal into right and left halves; mesial.

**3.**

*Statistics*Relating to or constituting the middle value in a distribution.

*n.*

**1.**A median point, plane, line, or part.

**2.**

*Statistics*The middle value in a distribution, above and below which lie an equal number of values.

**3.**

*Mathematics*

**a.**A line that joins a vertex of a triangle to the midpoint of the opposite side.

**b.**The line that joins the midpoints of the nonparallel sides of a trapezoid.

**me′di·an·ly**

*adv.*

## median

EBMThe exact middle value in a set of values that has been arranged in order from highest to lowest—i.e., there are as many values greater and less than the median. Where there is an even number of values, the median is designated as halfway between the two middle values.

Statistics

The midpoint of data after being ranked in a distribution, above and below which lie an equal number of values; a measure of central location, which divides a set of data into two equal parts; the data value at rank 0.5 x (n + 1).

The median is a better measure than the mean of the centre of a data distribution when the data are not symmetrically (normally) distributed, as it is not affected as severely as the mean by the outliers and non-symmetry typical of biological data. The median appears as a line in the box of a box-and-whisker plot and divides the middle two quartiles. Medians are compared by non-parametric statistical procedures.

## me·di·an

(mē'dē-ăn)**1.**Central; middle; lying in the midline.

**2.**The middle value in a set of measurements; like the mean, a measure of central tendency.

## median

**1.**Situated in or towards the MEDIAN PLANE of the body.

**2.**In statistics, the middle value when observations are ranked in order of magnitude.

## median

- (of a structure or character) describing a location along the line of bilateral symmetry
- (in statistics), the middle value in a frequency distribution, on either side of which lie values with equal total frequencies.

## me·di·an

(mē'dē-ăn)**1.**Central; middle; lying in the midline.

**2.**The middle value in a set of measurements.

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