AGRC1023 Lecture Notes - Lecture 3: Central Tendency, Scientific Control, Frequency Distribution
Document Summary
Real conditions o o o o o ncr o. Discrete (number of plants, cells or animals only integer values) Nominal (colours, sex, models of tractor, breed of sheep) don"t join nominal categories by lines when showing on plot graph. Ordinal (where order is implied shoe size, disease rating) o. Interval (years, ranks, values that don"t have a clear 0) Data collected as part of customer/client database typically for mailing, accounting or other purposes. Often missing data, no clear definitions or validation. Three ways of summarising data in a single value, by describing the central tendency of the distribution or data set: Mean average of all values, adding all values and dividing by the total number of values in the sample. Median the middle number of values in a sorted list of data. Also q2 (second quartile value) out of 4 quartiles this means that 50% of the data is smaller than that value, and 50% larger than that value.
