Note that when you have selected logarithmic transformation and the dose variable contains 0 values, these values cannot be represented in the graph as markers. Markers: click this option to have the data represented in the graph as markers. Dose-response plot: select this option to obtain a dose-response plot.This small number will be subtracted when the results are back-transformed for presentation. When the dose variable contains 0 values, MedCalc will automatically add a small number to the data in order to make the logarithmic transformation possible. Log transformation: select this option if the dose variable requires a logarithmic transformation.(Optionally) enter a data filter in order to include only a selected subgroup of cases in the analysis. Number of responses: select the variable that contains the number of responses for each dose.Total number of cases: select the variable that contains the number of measurements for each dose.
If your data are coded differently, you can use the Define status tool to recode your data. Response variable: the response variable must be binary or dichotomous, and should only contain data coded as 0 (no response) or 1 (response).
Select the option corresponding to the way you have entered the data: binary or grouped (see above). In the grouped format, you have 3 variables, one variable for the dose, one for the total number of measurements, and one for the number of measurements with a response. In the binary format, you have 2 variables, one variable for the dose (concentration) and one for the binary response.įor each single measurement, there is a row with the dose and the response, which is coded 0 (no response) and 1 (response). You can enter the data in binary format or in grouped format. MedCalc fits the regression coefficients a and b using the method of maximum likelihood.
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