When we gather lots of data bout some geologic process, we need to have a look at the data and consider its basic properties. To do this, we can use Statistics. This lecture will not do much justice to the study of statitsitcs or its application to geologic problems, but it should point you to an essential task when you consider your data.
You have to be careful however, that the description of your data (statistics) does not get in the way of your thinking.

I found this book to be useful:
Waltham, D., 1994, Mathematics: a simple tool for geologists, New York: Chapman and Hall, 189 p.

## Measures of location

These are representative of the data:
Mean = (1/n)*sum of all values
Mode = value which occurs with the greatest frequency
Median = the middle value of a set of numbers arranged in order

## Measures of dispersion

Range = xmax - xmin
Standard deviation is a measure of dispersion in the sample data: S2 = (1/(n-1))*Sum (x - xbar)2
xbar is the mean of the dataset.
+/- 3 standard deviations always contains >90% of the data. Units are the same as the data. Used to standardize the data set.

## Regression and plotting using Kaleidagraph

See assignment 6 for a summary of how Kaleidagraph may be used for regression.

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Prof. Ramón Arrowsmith