AS Biology 0.0 / 5 ? BiologySamplingASAQA Created by: LoisCreated on: 26-05-15 12:17 Problems with sampling Difficult to sample the whole population as too time consuming and impossible with mobile species 1 of 8 Why sample? make a representation of the whole society 2 of 8 How to prevent bias? Use a random number generator in order to generator number co-ordinates. Divide the area into a grid 3 of 8 How to ensure variation is not due to chance? It is important to analyse the results statisitcally. Large sample size 4 of 8 What is standard deviation? It is the variation around the mean, tells us how much a single sample varies 5 of 8 How do you measure SD? The width of the curve. The range of values around the mean. Point of inflection 6 of 8 What is mean? It is the average of the values collected in the sample. Useful when comparing one to another 7 of 8 SD? SQUARE ROOT OF sum of (x-mean)2/ n 8 of 8
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