[R] calculating area of ellipse

Michael Dewey ||@t@ @end|ng |rom dewey@myzen@co@uk
Tue May 11 19:06:03 CEST 2021


Dear Stephen

In that application the axes would be sensitivity and specificity (or 
their inverses) or some transformation of them like logits so the units 
would be the same. Whether the area has any scientific meaning I am not 
sure.

Michael

On 11/05/2021 15:20, Stephen Ellison wrote:
>> In doing meta-analysis of diagnostic accuracy I produce ellipses of confidence
>> and prediction intervals in two dimensions.  How can I calculate the area of
>> the ellipse in ggplot2 or base R?
> 
> There are established formulae for ellipse area, but I am curious: in a 2-d ellipse with different quantities (eg coefficients for salary and age) represented by the different dimensions, what does 'area' mean?
> 
> S
> 
> 
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