# A2 Data and their limitations Activities & Weblinks

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**Activities**

The following activities develop ideas about data.

These ideas are also referred to in other activities.

3.1 Diagnosing depression

3.1 Treating depression

3.3 The Mozart effect

3.3 Using fMRI

3.6 Exploring biodiversity

3.6 The Ordovician explosion

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**Weblinks**

**Errors**

Notes on the meaning of Reliability, Validity and Accuracy from BEEP http://www.beep.ac.uk/content/573.0.html.

Explanation of random and systematic errors in physical measurements

http://www2.selu.edu/Academics/Faculty/rallain/plab193/labinfo/Error_Analysis/05_Random_vs_Systematic.html

Explanation of random and systematic errors in social research

http://www.socialresearchmethods.net/kb/measerr.php

**Mean, median, mode and spread of data. Sampling**

A useful guide on how to read statistics for journalists, with explanations of things like standard deviation and margin of error.

http://nilesonline.com/stats/index.shtml

Very basic reminder on meaning of mean, median and mode from BBC

http://www.bbc.co.uk/schools/ks2bitesize/maths/data/mode_median_mean/read1.shtml

Explanation of measures of dispersion, range, interquartile range and standard deviation from the Open University

http://openlearn.open.ac.uk/mod/resource/view.php?id=163569

A useful glossary of statistical terms

http://www.stats.gla.ac.uk/steps/glossary/alphabet.html

**Presentation and analysis**

An explanation of box and whisker plots from an Open University course.

http://openlearn.open.ac.uk/mod/resource/view.php?id=165499

Another explanation of interquartile range and box and whisker plots

http://www.purplemath.com/modules/boxwhisk.htm

Some advice on the used of charts and graphs for health statistics.

http://www.health.state.pa.us/hpa/stats/techassist/tools.htm

An explanation of the scale on a log graph

http://www.intmath.com/Exponential-logarithmic-functions/7_Graphs-log-semilog.php