Skip to main content
. Author manuscript; available in PMC: 2008 Dec 15.
Published in final edited form as: J AOAC Int. 2006;89(1):22–34.

Table 5.

Second analyst precision (ruggedness test)

Day 1 precision, mg/100 g
Day 2 precision, mg/100 g
Days 1 and 2 precision combined, mg/100 g
Test material identification/replicates Campesterol Stigmasterol beta-Sitosterol Campesterol Stigmasterol beta-Sitosterol Campesterol Stigmasterol beta-Sitosterol
Saw palmetto pygeum lycopene complex tablets
1 117 108 316 122 119 328
2 122 112 329 131 121 348
3 132 121 351 122 117 329
4 116 108 315 125 117 335
5 124 116 324 119 109 320
6 122 115 328 125 118 337
 Mean 122 113 327 124 117 333 123 115 330
 SDa 5.74 5.05 13.1 4.10 4.12 9.54 4.85 4.76 11.3
 RSDr, %b 4.70 4.47 4.01 3.31 3.52 2.86 3.94 4.14 3.42
 Target RSDr lowb 3 3 2 3 3 2 3 3 2
 Target RSDr highb 4 4 3 4 4 3 4 4 3
 PRSDRc 5.47 5.53 4.72 5.46 5.51 4.71 5.46 5.52 4.71
 HorRatd 0.9 0.8 0.8 0.6 0.6 0.6 0.7 0.8 0.7

Saw palmetto (Serenoa repens) dried fruit CO2 extracts
1 40.4 22.7 145 43.2 25.6 157
2 42.0 26.6 151 42.6 24.0 152
3 42.7 25.5 153 43.1 24.7 155
4 42.8 25.8 154 43.9 25.2 159
5 42.6 24.9 153 44.3 25.1 159
6 44.0 25.9 157 40.3 25.5 145
 Mean 42.4 25.2 152 42.9 25.0 155 42.7 25.1 153
 SD 1.18 1.36 4.02 1.41 0.591 5.36 1.27 1.01 4.68
 RSDr, % 2.78 5.40 2.64 3.29 2.36 3.46 2.97 4.02 3.06
 Target RSDr low 3 3 3 3 3 3 3 3 3
 Target RSDr high 4 5 4 4 5 4 4 5 4
 PRSDR 6.41 6.93 5.29 6.40 6.94 5.28 6.40 6.94 5.29
 HorRat 0.4 0.8 0.5 0.5 0.3 0.7 0.5 0.6 0.6
a

SD = Standard deviation.

b

RSDr = Intralaboratory relative standard deviation.

c

PRSDR= 2 C−0.15, where C is the mean concentration expressed as a mass fraction.

d

HorRat = RSDr/PRSDR.