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Table 2 Exact figures from Microsoft Excel Worksheet used to calculate the sample size before (Student’s t = 2) and after iteration for heterorhabditid nematode-infected Galleria mellonella larvae

From: Towards optimization of entomopathogenic nematodes for more service in the biological control of insect pests

Case

E

a

x̄

B

n

T

t2

n+

1

0.2

1.2

4

0.9044

6.569076632

2

4

26.27630653

0.2

1.2

4

0.9044

6.569076632

2.06

4.2436

27.8765336

0.2

1.2

4

0.9044

6.569076632

2.052

4.210704

27.66043725

2

0.1

1.2

4

0.9044

26.27631

2

4

105.1052

0.1

1.2

4

0.9044

26.27631

1.983

3.932289

103.3260311

0.1

1.2

4

0.9044

26.27631

1.984

3.936256

103.4302692

3

0.1

1.2

1

0.9044

120

2

4

480

0.1

1.2

1

0.9044

120

1.965

3.861225

463.347

0.1

1.2

1

0.9044

120

1.965

3.861225

463.347

4

0.1

1.2

2

0.9044

56.15297662

2

4

224.6119065

0.1

1.2

2

0.9044

56.15297662

1.971

3.884841

218.1453859

0.1

1.2

2

0.9044

56.15297662

1.97095632

3.884668815

218.1357172

5

0.1

1.2

3

0.9044

36.01199651

2

4

144.047986

0.1

1.2

3

0.9044

36.01199651

1.97669220

3.907312

140.7101

0.1

1.2

3

0.9044

36.01199651

1.97705370

3.908741

140.7616

6

0.05

1.2

13

0.9044

28.89382

2

4

115.5753

0.05

1.2

13

0.9044

28.89382

1.9808

3.92356864

113.3669

0.05

1.2

13

0.9044

28.89382

1.9814

3.92594596

113.4356

  1. Estimates are calculated using the equations: n=(1/E)2 a x̄b − 2 or n+= (tα[n−1]/D)2 a x̄b − 2 where n or n+ is the sample size, E the standard error to mean ratio, D the ratio of the half-width of the confidence interval to the mean of the samples, a and b are the parameters of Taylor’s Power Law, x̄ the arithmetic mean of the heterorhabditid nematode-infected G. mellonella larval population in a soil sample, tα[n−1] is the appropriate Student’s t value for confidence limits of 1 − α and n − 1 degrees of freedom (http://www.danielsoper.com/statcalc3/calc.aspx?id = 10) for the insect population (Abd-Elgawad 2014)