Thanks for your response. Currently I’m using a gradient boosted trees method with default hyper-parameters listed in the table below. But you know what, I just ran study again and it seems the error mentioned above was caused by reading the .csv file in Microsoft Excel. This software interpreted the original value of the covariate in the .csv file (2.90603306754104e-05) as 2906033067,54104.
From the list of covariates generated by the model, 37 of the 71 total covariates were included (see part of the list in the image below).
Table with study specification
||Gradient Boosting Machine
||ntree:5000, max depth:4 or 7 or 10 and learning rate: 0.001 or 0.01 or 0.1 or 0.9
||Gender, Age, Age Group, Measurement Value (<5, <10)
||75% train, 25% test. Randomly assigned by person