Ontario Mathematics Proficiency Practice Test

The median of a data set is a measure of central tendency that represents the middle value. When dealing with an even number of values in a data set, the median is calculated by taking the average of the two middle values. This is necessary because there is no single middle value when the data set has an even number of entries; hence, the two central values must be averaged to find the median.

For instance, in a data set with the values arranged in ascending order, if there are eight values, you would need to identify the fourth and fifth values, then calculate their average to determine the median. This method ensures that the median accurately reflects the center of the data set, providing a better representation of the typical value.

The other options do not correctly describe how to calculate the median for a data set with an even number of values. They refer to other statistical measures or values that do not correspond to the definition of median.