Systematic errors: Consistent in one direction (always too high or always too low). Sources:
- Instrumental: zero error, calibration error
- Personal: parallax, reaction time
- Environmental: temperature effects on scale
Cannot be reduced by averaging. Must be identified and corrected.
Random errors: Unpredictable, equally likely positive or negative. Sources:
- Fluctuating experimental conditions
- Observer limitations
Reduced by taking multiple readings and averaging. Statistical analysis applies.
Gross errors: Mistakes in reading, recording, or calculating. Eliminated by careful practice and repeating measurements.