|
Descriptive statistics can be very useful in presenting and condensing
large amounts of data for preliminary inspection and basic interpretation.
They tend to describe measures of central tendency (e.g. mean, median)
and variability of the data (e.g. variance, standard deviation,
standard error). They are the simplest form of statistics and aid
in describing and summarising overall outcomes and presenting data.
The most useful descriptive statistics for flora and fauna surveys
are listed below:
- Frequency distribution - the number of times each
value of that particular variable occurs.
- Median - the value halfway through the ordered data set.
Half the data values lie above the median, and half below (i.e.
it is the centre of the data distribution).
- Mean (average) - the arithmetic middle point of
all observations. It is different to the median.
- Variance - a measure of the spread or dispersion of observations
about the mean.
- Standard deviation - a measure of the spread or dispersion
of observations about the mean. It is the square root of the variance.
- Standard error - another measure of the spread or dispersion
of observations about the mean. It is the standard deviation over
the population sample size.
It is common to present these types of data using graphs or tables.
back to "Types of statistical analysis"
|
