The output screens

28

multivariate analysis. When the centroids of these dummy variables are plotted along

with species scores in a CCA biplot, you have an ideal display of the relationships

between your classes, and the species that occur in them. Of course, any statistical

tests would be inappropriate.

6.5

Data set statistics

Summary statistics for both the raw and working data sets are displayed by clicking

on the Summary tab.

You can choose summary statistics for either the raw or working data sheets.

Statistics can be generated for Rows, columns and general summary statistics for the

data. These statistics are particularly useful prior to undertaking many analyses. For

example analyses should not be undertaken on a data set that comprises large

numbers of zeros. Use Summary statistics to determine the number of zero elements

in your data.

To obtain general statistics on the raw data select the Raw Data radio button in the

 Use  panel situated below the grid to select Raw Data.

Statistics for the individual rows and columns of either the raw or working data matrix

are selected using the Statistics radio buttons situated below the grid.

Values for each row or column are shown numbered in the order they appear in the

original data matrix. The statistics calculated are as follows:

Mean   This is the mean of all the values in the data matrix.

Median   This is the median of all the values in the data matrix.

Max   This is the maximum value in the data matrix.

Min   This is the minimum value in the data matrix.

Zeros   This is the number of zero entries in the data matrix.

Non zeros   This is the number of non zero entries in the data matrix.

% Zeros   (Number of zeros/Total number of cells) * 100

Sum   This is the sum of all the values in each row or column in the data matrix.

Copyright 2004  PISCES Conservation Ltd