plotnPV2 {bdpv} | R Documentation |
The function creates a plot from the results of the function nPV
.
plotnPV2(x, NPVlty = 1, PPVlty = 3, ...)
x |
an object of class |
NPVlty |
single integer value, the linetype for NPV sample size, see |
PPVlty |
single integer value, the linetype for PPV sample size, see |
... |
further arguments to be passed to |
Required sample sizes for different experimental settings and prevalences, needed to achieve a prespecified power can be calculated in dependence of the proportion of true negative and true positive compounds in the validation set, using function nPV
. This function draws a plot with the proportion of true positives on x and the total sample size on y, combining all parameter settings in one plot.
Note that for huge numbers of setting this should not work.
A plot.
Frank Schaarschmidt
Steinberg DM, Fine J, Chappell R (2009). Sample size for positive and negaitive predictiove value in diagnostic research using case-control designs. Biostatoistics 10, 1, 94-105.
plotnPV
, for sample sizes for several settings in one figure
TEST<-nPV(se=c(0.9, 0.92, 0.94, 0.96, 0.98), sp=c(0.98, 0.96, 0.94, 0.92, 0.90), pr=0.12, NPV0=0.98, PPV0=0.4, NPVpower = 0.8, PPVpower = 0.8, rangeP = c(0.05, 0.95), nsteps = 20, alpha = 0.05) plotnPV2(TEST, log="x")