FORMULA SHELF
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The arithmetic behind the work: what to measure, what to type in, and what the answer comes out as. Every formula says what the symbols mean and gives a worked example, so you can check it against a job you have already done.
SHELVES
Maths
1 formulas
Average daily milk yield, average egg weight, average tractor hours a week, average weight at weaning.
Weights of 180, 200, 220 and 240 kg give a mean of 210 kg.
Data
2 formulas
How spread out a set of readings is. A 500 litre herd with a standard deviation of 20 is steady; one with 120 is not. It is how you tell a genuinely consistent flock from a lucky average.
Readings 98, 100, 102, 100 give a mean of 100 and a standard deviation of about 1.6.
Averages lie when one reading is odd. The median tells you the typical day; the range tells you how variable the month was. Use both for milk records, daily temperatures and yields.
10, 12, 12, 13, 20 litres: median 12, range 10.
SOURCES & PROVENANCE
1 listed
This page is an AI-organised index. The label means the grouping and cross-links were compiled with AI; the information itself comes from the public-domain books, reports and manuals listed below. Open any source to read the local copy or follow the link to the original publication.