Hi Marcos and Nick,
Thank you very much for your responses. The number of observation is 128,745 (relatively big sample and hard to publish due to confidentiality issues also,sorry). The kdensity graph produced looks ok (pasted as new post due to space limitation) but looks like it does not have big difference (between the two groups) in terms of its visual pattern. I pasted the table with its note below. It says "ties exist in combined dataset....". From the third line (combined test), it looks like the two groups differ as you rightly stated but a significant p-value, both in (line 1 and 2) was not clear for me since we are talking about the same group (I guess). That means, if we reject the null in line 1 for group 1 being smaller than group 2, it seems not correct to reject the null in line 2 for group 1 larger than group 2. Sorry if I get lost with this test principle.
Two-sample Kolmogorov-Smirnov test for equality of distribution functions
Smaller group D P-value
-----------------------------------
1: 0.0148 0.003
2: -0.0155 0.002
Combined K-S: 0.0155 0.004
Note: Ties exist in combined dataset;
there are 15106 unique values out of 128745 observations.
Thank you very much for your responses. The number of observation is 128,745 (relatively big sample and hard to publish due to confidentiality issues also,sorry). The kdensity graph produced looks ok (pasted as new post due to space limitation) but looks like it does not have big difference (between the two groups) in terms of its visual pattern. I pasted the table with its note below. It says "ties exist in combined dataset....". From the third line (combined test), it looks like the two groups differ as you rightly stated but a significant p-value, both in (line 1 and 2) was not clear for me since we are talking about the same group (I guess). That means, if we reject the null in line 1 for group 1 being smaller than group 2, it seems not correct to reject the null in line 2 for group 1 larger than group 2. Sorry if I get lost with this test principle.
Two-sample Kolmogorov-Smirnov test for equality of distribution functions
Smaller group D P-value
-----------------------------------
1: 0.0148 0.003
2: -0.0155 0.002
Combined K-S: 0.0155 0.004
Note: Ties exist in combined dataset;
there are 15106 unique values out of 128745 observations.
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