Changes

Because the average is familiar and easily calculated, it is often chosen as the single number that summarizes a group. Depending on how the number is to be used, sometimes the average is a good choice, sometimes it is not, so it is important to understand the other choices.

Because the average is familiar and easily calculated, it is often chosen as the single number that summarizes a group. Depending on how the number is to be used, sometimes the average is a good choice, sometimes it is not, so it is important to understand the other choices.

*The median is the value which splits the group of numbers in the middle: half are higher, half are lower.

*The [[mid-range]] is the value which falls exactly half way between the two extreme values in the the group.

*The mode is the exact value which occurs the most often in the group; in a continuous distribution, it is the highest peak.

*The [[median]] is the value which splits the group of numbers in the middle: half are higher, half are lower. The median is the most commonly used [[quantile]].

*The [[mode]] is the exact value (or values) which occurs the most often in the group; in a continuous distribution, it is the highest peak.

*The average is also known as the ''arithmetic mean.'' There are other ''means.''

*The average most commonly used is known as the ''arithmetic mean.'' There are other ''means.''

**The [[geometric mean]] is used for "averaging" compound interest rates and in other percentage-growth situations.  

**The [[geometric mean]] is used for "averaging" compound interest rates and in other percentage-growth situations.  

**The [[harmonic mean]] is used when averaging speeds that are all measured along the same distance (rather than the same time).

**The [[harmonic mean]] is used when averaging speeds that are all measured along the same distance (rather than the same time).