# 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

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

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 