Fuels & Lubricants Magazine
Issue No. 2, June 2018
Issue No. 2, June 2018
Create successful ePaper yourself
Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.
Table 4: Sample „DS”, different days<br />
No. of<br />
measurement<br />
DCN<br />
1 52.00<br />
2 52.32<br />
3 52.30<br />
4 51.96<br />
5 51.49<br />
6 51.60<br />
7 51.34<br />
8 51.41<br />
9 51.57<br />
10 51.44<br />
51.74<br />
s 0.37<br />
t tab (0.05, 9) 2.262<br />
s ∙ t tab 0.84<br />
r (ASTM D7668) 1.42<br />
s ∙ t tab < R<br />
✓<br />
Tables 5 – 8 show the results of the<br />
evaluation of accuracy and reproducibility<br />
(R).<br />
Table 5: CRMs<br />
DCN<br />
CRM 73 (Lot 1049) CRM 74 (Lot 1052)<br />
“true” value 58.38 ± 0.26 (= 58.4) 52.57 ± 0.22 (= 52.6)<br />
1. measurement 57.93 52.50<br />
2. measurement 58.13 52.18<br />
x − 58.03 (= 58.0) 52.34 (= 52.3)<br />
s 0.14 0.23<br />
|true value - x − | 0.35 0.23<br />
R (ASTM D7668) 1.71 1.45<br />
R (ASTM D7668) /√2 1.21 1.03<br />
| true value - x − | < R ✓ ✓<br />
| true value - x − | < R /√2 ✓ ✓<br />
T cal 3.5 1.4<br />
t tab (0.05, 1) 12.706 12.706<br />
The t-test for the comparison<br />
of a “true” value with a group of<br />
results gave the following result: t cal<br />
< t tab (0.05, 1). Therefore, there is no<br />
significant difference between the<br />
average value ( x − ) and “true” value.<br />
Table 6: Samples from RR (DIN-FAM)<br />
Sample<br />
DCN<br />
CN<br />
(CFR)<br />
Δ<br />
R (ASTM<br />
D7668)<br />
R (ISO 5165 /<br />
ASTM D 613)<br />
M1 (2704/14) 53.42 51.20 2.22 1.50 4.20 4.04<br />
M4 (1810/14) 52.02 53.70 -1.68 1.44 4.51 4.29<br />
M5 (2386/14) 51.09 51.20 -0.11 1.39 4.20 4.01<br />
M6 (2429/14) 53.71 55.20 -1.49 1.51 4.70 4.47<br />
D5 (671/13) 51.97 52.02 -0.05 1.43 4.30 4.11<br />
D6 (670/13) 52.19 51.55 0.64 1.44 4.24 4.06<br />
R xy<br />
<strong>Fuels</strong>&<strong>Lubricants</strong> No. 2 JUNE 2018 27
Change language