Final answer:
The likely causes of an error in a plotted point on a standard curve are instrument calibration or sample contamination. Instrument calibration issues would cause systematic errors impacting accuracy, while sample contamination would introduce random errors affecting precision.
Step-by-step explanation:
If a student has made an error in their plotted point on a standard curve, considering measurement precision, instrument calibration, sample contamination, and experimental design, the error is likely due to either instrument calibration or sample contamination. Systematic errors, which are constant errors such as those introduced by instruments that are not properly calibrated, can cause points to deviate consistently from the expected values. Sample contamination, on the other hand, can introduce variability that is not consistent with the instrument's calibration or the procedural design.
Instrument calibration issues imply that the tools used to measure may have given consistent but incorrect readings. This type of error affects the accuracy of the measurements, leading to a skewed standard curve.
Sample contamination could introduce erratic results that are not representative of the true relationship intended to be analyzed by the standard curve. It's usually more of a random error, affecting the precision of the measurements.
Options like measurement precision and experimental design may also contribute to error, but they usually result in different types of issues. For example, if the precision is at fault, it might be due to the limitation of the measuring device or the skill of the person making the measurement. An experimental design error could refer to issues like having too few data points or not having proper control in the experiment.