Researchers have studied the ecology of ponds in rural Bangladesh. Of particular interest in such studies are the zooplankton, phytoplankton, and copepod counts (per liter of water) in these ponds. Copepods are a particular type of zooplankton that are thought to be a natural reservoir of cholera bacteria, but copepod counts can be difficult to obtain in laboratory analyses; total zooplankton counts are easier to obtain. It is also believed that copepod counts will be related to phytoplankton counts since copepods feed on phytoplankton.
The data here show zooplankton, phytoplankton, and copepod counts for 100 water samples from ponds in rural Bangladesh.

a. Find the estimated least-squares equation for the regression of copepod count on zooplankton count.
b. Test the null hypothesis that the true slope is zero, at the α = .05 significance level. Interpret your result.
c. Find a 95% confidence interval for the true slope in part (a). Interpret your result.
d. Find the estimated least-squares equation for the regression of copepod count on phytoplankton count.
e. Test the null hypothesis that the true slope in part (d) is zero, at the α = .05 significance level. Interpret your result.

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Obs Copepods Zooplankton PhytoplanktonbsCopepods Zooplankton Phytoplankton 1,710 1,080 1,308 28, $0. 30 17. 09. 16. 50. 17 44-28 23 14 999·197 199 43 9. 20 m 104 32-an 36 2 31 89 99 512 21 39 220 198 004 52 79 17 100 57彬97 750 15 34 84 600 125 125 900 19 86 201 93 250仍幯66 201繃199二緗201 400锐ぷぷ360 170 EST 26 50 60功84 36 250 26 4 8 3 196 $20 3 2 8 36 70 78 20 97 15 27 17 ssi惻5 87 81 62 400 29 42 250 400 71 30 62 50 “ 54 48 150 96 90 197 43 43 Oba-55 53 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 8 2 3 4 5 86 7 8 9 90 91 92 93 94 95 96 97 98 99 100 den pha 96 30 02 77 45 46 2 49 18 04 61 06 92 9 2 4 1 01 37 6 8 6 8 04 37 98 87 6 7 9 02 99 45 00 2 9 8 5 8 8 9 5 0 07 63 3 1 4 % 5 26 49 86 125 009 101 89 33 69 27 360 26 42 33 99 65 25 1 5 8 97 63 41 300-80 62 49 28 8 40, 110 17 63 10 007 81 37 35 12 74 44 53 360 1 997 997 998 86 7M 996硎36谢矊360 250 45 210 1m2娜50 27 195 74 3 996 3 996 17 196 196獺84罡500 떪 750 004 46 201 201 58 111 8 3 2 3 7 7 3 5 8 5 2 120 60 44 30 000 18 198 46 33 58 39 250 120 360 220 90 197 ros 15 12 74 66 41 92 12 120 29 18 220 18 66 3: Ob | 1 2 3 5 6 7 S 9 0 1 2 3 4 5 6 7 1 19 20 24 25 26 27 28 29 30 31 32 33 커 35 36 37 38 39 40 4 42 44 45 46 47 48 49 22