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limdil: Limiting Dilution Analysis


This page performs a Limiting Dilution Analysis using the limdil function in the statmod package which is part of the statistical package, R. The technical report can be found here and its supplementary material which describes the mathematical algorithm implemented can be found here.

The data to be entered is a list of four numbers per line, separated by commas, spaces or tabs, in the following order.

1. The Expected number of cells in assay,
2. The number of trials at each dose,
3. The Count of positive cases out of those tested,
4. Optional: The group to which the response belongs if there is more than one group.

You can type or copy and paste from a text document or an Excel spreadsheet.
Enter your data in this box:


 Enter level for confidence interval (default = 0.95)
 Check box if need to test for non-equality in frequency between multiple groups (default = No)
 Check box if the adequacy of the single-hit model should be tested (default = No)
 Check box if it is the actual number of cells observed (default = No)



An example for single group analysis is shown below:

Enter the following input, then select the model test check box, but not the observed check box.

50 24 2
100 24 6
200 24 9
400,24,15
800,24,21

Output:

Confidence Intervals.
Lower Estimate Upper
537.74 403.06 302.1166

Test Unit Slope Result.
Chisq P.value Degree of Freedom
0.0666993 0.7962047 1


An example for multiple groups analysis is shown below:

Enter the following input, then select the single hit model test check box and the multiple groups check box but not the observed check box.

30000 6 2 A
20000 6 3 A
4000 6 2 A
500 6 1 A
30000 6 6 B
20000 6 5 B
4000 6 6 B
500 6 1 B
30000 6 2 C
20000 6 3 C
4000 6 4 C
500 6 2 C

Output:

Confidence Intervals.
Group Lower Estimate Upper
A 67165.43 31863.53 15116.177
B 10251.79 4508.96 1983.140
C 44525.85 22491.41 11361.118

Test Unit Slope Result.
Chisq P.value Degree of Freedom
2.442388e+01 7.730458e-07 1

Test Result of Overall Groups Difference.
Chisq P.value Degree of Freedom
1.808080e+01 1.185233e-04 2

Test Result of Pairwise Groups Difference.
Group 1 Group 2 Chisq P.value Degree of Freedom
A B 16.69911 4.380163e-05 1
A C 0.5490186 0.458719 1
B C 12.38758 0.0004321989 1

Comments/Questions? Email < Keith Satterley.>
This is the version released on 07 April 2008. Please report any problems.
01 September 2008