The functions DA2y and y2DA are convenience functions that
convert the estimates of intercept, slope and sd from the regression of
\(D=y_1-y_2\) on \(A=(y_1+y_2)/2\), back and forth
to the resulting intercept, slope and sd in the relationship between
\(y_1\) and \(y_2\), cf. Carstensen (2010), equation 6.
Usage
y2DA(A = 0, B = 1, S = NA)
Value
y2DA returns a 3-component vector with names
c("DA-int","DA-slope","DA-sd"), referring to differences
D=y1-y2 as a linear function of A=(y1+y2)/2.
Arguments
A
Intercept in the linear relation of y1 on y2.
B
Slope in the linear relation of y1 on y2.
S
SD for the linear relation of y1 on y2. Can be NA.
#' y2DA takes intercept(A), slope(B) and sd(S) from
the relationship y1=A+B y2 + E with sd(E)=E, and
returns a vector of length 3 with names
"int(t-f)","slope(t-f)","sd(t-f)", where t refers to "to"
(y1 and f to "from" y2.
References
B. Carstensen: Comparing methods of measurement: Extending the
LoA by regression. Stat Med, 29:401-410, 2010.