Skip to main content

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 valueNumber of samples via (D)++Improvement in sample size
Pratylenchus spp.: the power law parameters a = 1.58, b = 1.33
11582 (assumed)632609 and 209 instead of 632 and 215 samples, respectively
1.964 (n = 632)609
1.9638 (n = 609)609
5542 (assumed)215
1.971 (n = 215)209
1.971 (n = 209)209
M. incognita: the power law parameters a = 2.92, b = 1.47
51242 (assumed)498480 and 375 instead of 498 and 388 samples, respectively
1.966 (n = 498)480
1.965 (n = 480)480
8972 (assumed)388
1.966 (n = 388)375
1.966 (n = 375)375
  1. The t value is either assumed as 2 for 95% confidence interval or iterated using its tabulated value from http://www.danielsoper.com/statcalc3/calc.aspx?id=10
  2. +Based on a sample size of 100 gm soil (based on data reported by Abd-Elgawad et al. (2008)
  3. ++The fractional values rounded up to nearest integer