Posted By Yuri Tsvetnenko on July 22, 2002 at 22:46:09:

In Reply to: Significant difference between LC50s? posted by Amy Mahar on July 18, 2002 at 12:13:51:

Test for significance of differences between LC50 values is discribed in:
Greenberg AE, Eaton AD, Clesceri LS (eds.) Standard methods for the examination of water and wastewater. 1992. 18th Edition, American Public Health Association, Washington, DC.

The test involves the following calculation:
f(1,2) = 10^{[log f(1)]^2 +[log f(2)]^2}^0.5,
where:
f = factor for 95% confidence limits of LC50, i.e., the confidence limits are LC50*f and LC50/f (f = antilog of two standard deviations of the log LC50).
If the ratio (greater LC50)/(smaller LC50) exceeds the value for f(1,2), the LC50s are significantly different.

Note that confidence limits about the LC50 do not describe variability of the LC50 under conditions other than those tested.

Follow Ups

Post Followup