AOAC SPIFAN Nutrients ERP (December 7, 2022)

Amino-07 (SLV) 10-2022 FOR ERP USE ONLY DO NOT DISTRIBUTE

degrees of freedom (Satterthwaite approximation) = � 2 + � � 2 � 2

eqn 19

1 − 1 � 2 � 2 + 1 − 1 �� � 2 � 2

where: = number of degrees of freedom =

standard deviation of differences between the measured results and reference value = number of replicate analyses = uncertainty of the reference value = coverage factor used for calculating the expanded uncertainty − 1 = calculated for , using a two- sided t- distribution at α = 0.05. = p -value; probability of observing data at least as extreme as test statistic Γ = cumulative Student’s t- distribution function = test statistic; expression using sample estimates of characteristics of the population = number of degrees of freedom from Satterthwaite approximation = Γ ( , )

p -value

eqn 20

= ± 1.96 × where: = limit of agreement =

Bias against reference method limit of agreement

eqn 21

mean of value of data set =

standard deviation of data set

0 : = 0

hypothesis test

eqn 22 where: 0 = hypothesised difference in measured results between methods = mean difference between test methods or between test method and reference value where: = test statistic; expression using sample estimates of characteristics of the population = mean of the differences between the measured results for each method = standard deviation of the differences between the measured results for each method = number of replicate pairs of results = / √ eqn 23

test statistic