Description Usage Arguments Details Value References See Also Examples
ciROC
constructs confidence interval
of receiver operating characteristic (ROC)
curve. This is an S3 method defined for object of class "rocit"
.
1 2 
object 
An object of class 
level 
Level of confidence, must be within the range (0 1). Default is 0.95. 
nboot 
Number of bootstrap samples, used to estimate 
... 

For large values of n_Y and n_{\bar{Y}}, the distribution of TPR(c) at FPR(c) can be approximated as a normal distribution with following mean and variance:
μ_{TPR(c)}=∑_{i=1}^{n_Y}I(D_{Y_i}≥q c)/n_Y
V ( TPR(c) )= \frac{ TPR(c) ( 1 TPR(c)) }{n_Y} + ( \frac{g(c^*)}{f(c^*) } )^2 * K
where K=\frac{ FPR(c) (1FPR(c))}{n_{\bar{Y}} } , g
and f are the probability distribution functions of
the diagnostic variable in positive and negative groups
(with corresponding cumulative distribution functions G and F),
c^*=S^{1}_{D_{\bar{ Y}}}( FPR(c) ), and S is the survival
function given by: S(t)=P(T>t)=1F(t). density
and
approxfun
were used to approximate PDF and CDF
of the diagnostic score in the two groups and the inverse survival
of the diagnostic in the negative responses.
For "binomial"
type, variance of A+BZ_x is given by
V(A)+Z_x^2V(B)+2Z_xCov(A, B). Bootstrap method was used to estimate
V(A), V(B) and Cov{A,B}. The lower and upper limit of
A+BZ_x are inverse probit transformed to obtain the confidence interval
of the ROC curve.
A list of class "rocci"
, having following elements:
'ROC estimation method“ 
The method applied to estimate ROC curve in the

'Confidence level' 
Level of confidence as supplied as argument. 
FPR 
An array containing all the FPR values, for which TPR and confidence interval of TPR were estimated. 
TPR 
Array containing the TPR values associated with the FPR values. 
LowerTPR 
Lower limits of the TPR values. Forced to zero for

UpperTPR 
Upper limits of the TPR values. Forced to one for

Pepe, Margaret Sullivan. The statistical evaluation of medical tests for classification and prediction. Medicine, 2003.
plot.rocci
, rocit
, ciAUC.rocit
1 2 3 4 5 6 7 
Add the following code to your website.
For more information on customizing the embed code, read Embedding Snippets.