4Processing KODAK Motion Picture Films, Module 3, Analytical Procedures

VISUAL TITRATION STATISTICS

Repeatability Standard Deviation, 1sr and

95 Percent Confidence Estimate

Repeatability standard deviation is an estimate of the

variability one trained analyst should be able to obtain under

favorable conditions (analyzing a sample, with one

instrument, within one day).

HYPO INDEX (3.0 mL)
Samples (Process
ECN-2 Fixer) Mean Level
(mL 0.1 N I2)(N) Repeatability Standard
Deviation, 1Sr
(mL 0.1 N I2)
95 Percent
Confidence Estimate
(mL 0.1N I 2)
“Fresh” at “Aim”29.42 5 0.089 ± 0.25
“Seasoned”, As
Received 47.29 5 0.060 ± 0.17
“Seasoned” with
Standard Addition 57.65 5 0.084 ± 0.23
THIOSULFATE (S2O3
=
)
Samples (Process
ECN-2 Fixer) Mean Level
(g/L S2O3
=
)(N) Repeatability Standard
Deviation, 1Sr
(g/L S2O3
=
)
95 Percent
Confidence Estimate
(g/L S2O3
=
)
“Fresh” at “Aim”81.37 5 0.10 ± 0.28
“Seasoned”, As
Received 125.29 5 0.24 ± 0.67
“Seasoned” with
Standard Addition 155.73 5 0.19 ± 0.53
SULFITE (Na2SO3)
Samples (Process
ECN-2 Fixer) Mean Level
(g/L Na2SO3)(N) Repeatability Standard
Deviation, 1Sr
(g/LNa2SO3)
95 Percent
Confidence Estimate
(g/L Na2SO3)
“Fresh” at “Aim”16.08 5 0.18 ± 0.50
“Seasoned”, As
Received 28.93 5 0.24 ± 0.67
“Seasoned” with
Standard Addition 33.43 5 0.31 ± 0.86

Bias

Bias is a statistically significant deviation of the mean from

the known mix level at a 95percent confidence level. It is

determined for “fresh” samples only. Bias is not determined

for “seasoned” samples, since the component concentration

level was not determined independently of the test method.

Statistically significant biases were found for hypo index,

thiosulfate, and sodium sulfite (see the table below) for a

“fresh” tank Process ECN-2 Fixer sample. However, the

individual biases for hypo index, thiosulfate, or sodium

sulfite were judged not to be practically significant.

Analyte Bias
(Measurement Unit of Analyte) Bias
(%)
Hypo Index
(mL 0.1 N I2)– 0.82 – 2.71%
Thiosulfate
(g/L S2O3
=
)– 0.696 – 0.85%
Sodium Sulfite
(Na2SO3)– 1.322 – 7.6%