Table 1 Improvement in minimum number of nematode samples needed to achieve a 10% level of reliability as defined in terms of standard error to mean ratio (E) or confidence interval half-width to mean ratio (D) with iteration
From: Factors affecting success of biological agents used in controlling the plant-parasitic nematodes
Mean count per sample+ | Number of samples via (E) | Student’s t value | Number of samples via (D)++ | Improvement in sample size |
|---|---|---|---|---|
Pratylenchus spp.: the power law parameters a = 1.58, b = 1.33 | ||||
1 | 158 | 2 (assumed) | 632 | 609 and 209 instead of 632 and 215 samples, respectively |
1.964 (n = 632) | 609 | |||
1.9638 (n = 609) | 609 | |||
5 | 54 | 2 (assumed) | 215 | |
1.971 (n = 215) | 209 | |||
1.971 (n = 209) | 209 | |||
M. incognita: the power law parameters a = 2.92, b = 1.47 | ||||
5 | 124 | 2 (assumed) | 498 | 480 and 375 instead of 498 and 388 samples, respectively |
1.966 (n = 498) | 480 | |||
1.965 (n = 480) | 480 | |||
8 | 97 | 2 (assumed) | 388 | |
1.966 (n = 388) | 375 | |||
1.966 (n = 375) | 375 | |||