I hope I can phrase my question intelligibly
three groups of sample for a total of 192 individuals - group 1: 40 individuals; group 2: 82 individuals; group 3: 70 individuals.
the 95% CI range of disease-free period after treatment - group 1: 9-14.7 months (median: 12.8); group 2: 5.3-7.6 months (median: 5.7); group 3: 3.6-5.5 months (median: 5.2).
the CI ranges were derived from certain distribution (what kind??) of individual's response (i.e. diseaes-free period) to the treatment. The 'response distribution' is assumed continuous but not the same
(new edit) across all three groups (the new edit is a result of my plotting of a putative response distribution for these three groups. as the medians for group 2 and 3 are close, 5.7 v 5.2, but the differences between the median and the upper/lower end of CI are different - group 2: [5.7-5.3],[7.6-5.7]; group 3: [5.2-3.6],[5.5-5.2], I assumed the response distribution for group 2 is right-skewed and that for group 3 is left-skewed). The response distribution for group 1 is left-skewed)
Now more people were enrolled into the three groups without changing significantly the ratio (40:82:70). The total number of individuals is now 1920. Assuming the larger group (of 1920 individuals) has the same/similar distribution of their responses to the treatment as those of the smaller group (of 192 individuals).
Does the 95% CI range of disease free period change due to an increase of the sample size? If yes, is it possible to estimate the 95% CI range of disease free periods for the three groups ?
Any insight to share will be greatly appreciated.