Final answer:
Some sources of error when using a hemocytometer include irregularities in the measured objects and any other factors like defective counting devices that can influence the count. Chance error from a small sample size and bias from non-random sample selection can also affect accuracy.
Step-by-step explanation:
When using a hemocytometer, some sources of error include irregularities in the object being measured, such as the size and shape of red blood cells (RBCs), which can influence the accuracy of cell counts. Additionally, any other factors that affect the outcome can introduce errors. For example, a defective counting device, such as a damaged hemocytometer or improper calibration of a cell counter, can cause nonsampling errors affecting the count.
In cases where a sample is being studied rather than the entire population (as a practicality in many lab settings), a chance error may occur if the sample size is too small, which doesn't fairly represent the entire population. Bias is another source of error and is usually due to samples not being selected randomly, thus influencing the study's result.