Zooplankton and Phytoplankton. Refer to the table below for Exercises 42 and 43. Meta-analysis refers to the statistical analysis of a set of similar research studies. In a meta-analysis, each data value represents an effect size calculated from the results of a particular study. The table contains effect sizes calculated in a meta-analysis for zooplankton and phytoplankton.11 Not surprisingly, the paper found that zooplankton biomass was reduced by the introduction of zooplanktivorous fish (that is, fish that eat zooplankton), but that phytoplankton biomass increased, because there were now fewer zooplankton, and the zooplankton eat the phytoplankton. Such an effect is called a trophic cascade. See if you can replicate the scientists' results in the following exercises.
| Zooplankton | Phytoplankton | ||
|---|---|---|---|
| −2.37 | −3.00 | 10.61 | 3.04 |
| −0.64 | −0.68 | 2.97 | 0.65 |
| −2.05 | −1.39 | 1.58 | 2.55 |
| −1.54 | −0.64 | 2.55 | 1.05 |
| −6.60 | −3.88 | 5.67 | 2.11 |
| 0.26 | 1.57 | ||
plankton
43. Test whether the population means effect sizes differ, at level of significance .
10.2.43
. Reject if the . . (TI-84: 0.000092880601). The is , so we reject . There is evidence at level of significance that the population mean effect sizes of zooplankton differs from that of the phytoplankton.