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| Mean, Median, Mode and Range |
When scores are tabulated into
a frequency distribution, calculation of measures of central tendency (or
central position) follows. Measures of central tendency can be better
understood this way, for example, if we compress the entire distribution at one
single point, then that single point represents the central tendency. Measures
of central tendency are sometimes called measures of central location.
Score is the measurement of
individual performance by means of tests. And when scores are expressed in
equal units, they form an interval scale.
The value of a measure of
central tendency serves two purposes. First, it is an “average” which
represents all the scores. Second, it enables the researcher to compare two or
more groups in terms of typical performance.
There are three “averages’ or
“measures of central tendency” which are in common use. These are: (1) Mean,
(2)
Median, and (3) Mode.
Mean: It is an “arithmetic”
mean. Mean is probably the most familiar average. The mean (of a set of scores)
is the sum of separate scores (or measures) divided by their number. It is used to describe the middle of a set of
data.
Advantage of Mean:
1. Most popular measure.
2. It is unique, there is only one
answer.
Disadvantage of Mean:
1. It is affected by extreme
values/scores.
Median: It is a “positional”
average. When ungrouped scores (also known as raw data) are arranged in order
of size, the median is the midpoint in the series. It is a measure of position
rather than of magnitude.
Advantage of Median:
Extreme values do not affect
the median as strongly as they affect the mean.
Disadvantage of Median:
It takes relatively long time
to calculate for a very large set of data.
Mode: It is a “democratic” average.
It is defined as the most frequently occurring score in a distribution. If
there is only one value which occurs a maximum number of times, then the
distribution is said to have one mode.
Advantage of Mode:
1. It is easy to understand and
simple to calculate.
2. It is not affected by extreme
large or small values.
3. It can be useful for
qualitative data.
Disadvantage of Mode:
1. It is not used more frequently
as compared to mean and median.
2. It is not necessarily unique;
there may be more than one answer.
3. When no values repeat in the
data set, the mode is every value and is useless.
4. When there is more than one
mode, it is difficult to interpret and compare.
