Volumetric analysis question

[katiesaliba]

Hey guys,
What are some possible sources of error in a titration experiment (with a dilution)? And what should I include in my definition of a standard solution?

[Sense]

Contamination in the conical flask can cause incorrect readings.
Parallax error - Meaning you don't align your eyes with the equipment correctly, therefore getting the wrong readings from the burette.
Problems with the equipment (Systematic Error)
Air bubbles - Cause wrong readings

A standard solution is a solution that has a known concentration of the substance being used.