Message-ID: <A4E5A0B016B8CB41A485FC629B633CED4694ECB29D@GOLD.corp.lgc-group.com>
Date: 2012-07-24T09:19:42Z
From: S Ellison
Subject: limit of detection (LOD) by logistic regression
In-Reply-To: <500e55fc.0464b40a.19ab.ffffb9a3@mx.google.com>
> set 1; however the figure obtained from the sample set 2
> shows that interpolation is not correct.
I don't think the interpolation is incorrect; what is making it look incorrect is using a straight line to represent a logistic regression.
Try adding the predicted values for the line to your plot:
lines( dil <- 10^seq(-1, 6, 0.05), predict(model, newdata=data.frame(dilution=dil), type="response"))
S Ellison
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