Final answer:
Measured data contain errors due to limitations in measurement precision, human factors, and other factors specific to the situation.
Step-by-step explanation:
All measured data contain some error due to limitations in measurement precision and human factors. Limitations of the measuring device and the skill of the person making the measurement both contribute to the uncertainty in the data. Additionally, irregularities in the object being measured and other factors specific to the situation can also affect the outcome. To minimize random errors, scientific measurements are usually taken at least in triplicate and averaged.