Q2. A student calculated a weight percentage of acetic acid in the dressing of 2.3 %w/v. Considering that commercial salad dressings range from 4-8 %w/v, this value is slightly low and an error has likely occurred.

Assign the following sources of error into the three categories (i.e. in the table, enter in the category number, without the full stop):

1. An experimental/scientific source of error. Difficult to avoid without significant experimental changes.
2. Operator/human error. Likely to cause only minor deviations and can likely be corrected for with sufficient care and training.
3. An insignificant source of error.