1.9:
Random and Systematic Errors
Errors in the measurement process are a common problem. Such errors may fall into two categories: Random and Systematic.
Random errors are the result of inconsistency in the measuring process or variations in the quantity being measured. These result in fluctuations, too high or too low, around the true value.
Consider a scientist measuring the length of an earthworm using a caliper. Inconsistency of the scientist to read the scales correctly, or continuous body movement of the earthworm during the measurement, may result in incorrect length measurements.
Random error cannot be avoided, however, it can be averaged out with repeated trials.
Systematic errors are the results of a persistent issue and lead to a consistent discrepancy in measurement. These errors tend to be either all too high or all too low compared to the true value. For instance, weights being measured using an improperly calibrated weighing balance.
These are predictable and mostly instrument-related. However, unlike random error, it cannot be averaged out with repeated measurement.
1.9:
Random and Systematic Errors
Scientists always try their best to record measurements with the utmost accuracy and precision. However, sometimes errors do occur. These errors can be random or systematic. Random errors are observed due to the inconsistency or fluctuation in the measurement process, or variations in the quantity itself that is being measured. Such errors fluctuate from being greater than or less than the true value in repeated measurements. Consider a scientist measuring the length of an earthworm using a ruler. Random error in this measuring process could be the result of the inconsistent method in which the scientist reads the scales, or if the earthworm is moving. Random error cannot be avoided; however, it can be averaged out with repeated trials.
Systematic errors arise from a persistent issue and result in a consistent discrepancy in measurement. These errors tend to be consistently either greater than or less than the true value. These are predictable and are mostly instrumental in nature. For instance, an improperly calibrated weighing balance may consistently weigh objects heavier than their true value. Unlike random error, systemic errors cannot be averaged out with repeated measurements.
This text is adapted from Openstax, Chemistry 2e, Section 1.5: Measurement Uncertainty, Accuracy, and Precision.