Filter out insufficient data scenarios
ministat
fails with exit code 2, and the message Dataset /tmp/beforei7dki3_i must contain at least 3 data points
when we have insufficient data.
This MR filters out insufficient data: any population size less than 3.
Extra fixes
- Convert input to string before sending the message to the logging module.
- Log errors with stderr when ministat binary fails.
Edited by Guilherme Gallo