MEAN
The mean is the most widely spread
measure of central tendency. It is the
simple
average of the dataset.
Note: easily affected by outliers
The formula to calculate the mean is:
In Excel, the mean
is calculated by:
=AVERAGE()
MEDIAN
The median is the midpoint of the ordered
dataset. It is not as popular as the mean, but is often used in academia and data science.
That is since it is not
affected by outliers.
In an ordered dataset, the median is the number at position
MODE
The mode is the value
that occurs most often. A dataset can have
0 modes,
1 mode or multiple modes.
The mode is calculated simply by finding the value
with the highest frequency
In Excel, the mode
is calculated by:
=MODE.SNGL() ->
returns one
mode
=MODE.MULT() ->
returns an array with
the modes. It is used when we have more than 1 mode
in Excel:
=SKEW()
Skewness is a measure
of asymmetry that indicates
whether the observations in a dataset are
concentrated on one side.
Right (positive) skewness looks like the one in the graph. It means that the outliers
are to the right (long tail to the right).
Left
(negative) skewness
means that the outliers are to the left. Usually, you will use software to calculate
skewness.
Formula to calculate skewness:
