What are two main purposes for using repetition when conducting experiments A - recording data easilyB - increasing confidence in results and recording data easilyC - reducing mistakes and increasing confidence in resultsD - saving time and increasing confidence

The answer is the option C reducing mistakes and increasing confidence in results.

Justification: all measurements have errors. Some are random errors from the operation of the instruments or change of the enviroments or human mistakes. If you repeat the measurement several or many times you reduce the random errors and consequently increase the confidence in the results.