The standard deviations for the data in Table P2.4 have been calculated for you. Do these calculations for yourself, showing your working fully.

Table P2.4

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1 Calculate x x y for each set of values. Number of Number of Quadrat species P, species Q, ху y 10 21 210 2. 9. 20 180 11 22 242 4 Add up all the values of xy, to find Exy. 4 7 17 119 8 16 128 14 23 322 7 10 20 200 8 12 24 288 12 22 264 2 Calculate the means for each set of figures, I and y. 5 Now calculate the standard deviation, s, for each set of figures. The method for doing 10 9 19 171 x= 10.2 y= 20.4 mean 10 x 10.2 x 20.4 Σν-2124 nxy = 2080.8 standard deviation s, = 2.10 S,=2.55 this is shown in Table 3 Calculate nxy. Exy-nxy r= P2.1 on page 498. Here, n = 10, x = 10.2 and ns,5y y = 20.4, so = 2124 - (10 x 10.2x 20.4) 10x 2.10 x 2.55 = 2124 - 2080.8 nxy = 10 x 10.2 x 20.4 6 Now substitute your numbers into 53.55 the formula and = 43.2 53.55 calculate r. = 0.81