1. Andrew Mead (School of Life Sciences) LDC Statistics Seminars, 2013/4 Measurements, Meaningfulness and Scale Types

2. The Nature of Measurement 2  All studies (experiments or surveys) involve some sort of measurement  Important part of the planning for any study  What are you going to measure?  How accurately can you measure it?  What is the precision of your measurements?  Can you measure what you are really interested in?  How do the data relate to the real response of interest?  Different types of measurement require different statistical approaches  Important to consider method of analysis when planning the form of measurement

3. How far is an Irish mile? Knappogue Castle, Co. Clare 3

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6. EnglishIrishRatio Quin2¼1¾1.286 Spancilhill6¼6¼ 51.250 Ennis8½6½6½ 1.308 Kilkishen43½3½ 1.143 Sixmilebridge5¾5¾ 4½4½ 1.278 Limerick15 ½ 12 ¼ 1.265 Mean ratio =1.255 => 1 Irish mile = 2208 yds In fact, 1 Irish mile = 14/11 (= 1.273) English miles! EM = 1760 yds; IM = 2240 yds 6

7. The Need for Statistics 7  Statistical methods have been developed to help in the quantitative study of variation and the summary, analysis and interpretation of data from experimental and observational studies.  Important to understand the nature of the measurements being made to be able to identify the most appropriate method of analysis  Important to also consider the nature of measurements for the presentation of data and the results of analyses