A student read liquid volume while viewing above eye level. Which error may occur?

Correct answer: Parallax error

Parallax error occurs when a scale is viewed from an angle instead of from the correct position. In a liquid container, the apparent position of the meniscus can shift when the eye is above or below the liquid level. The observer may then record a value that is higher or lower than the actual volume, even though the instrument itself has not changed. To reduce this error, place the eye at the same height as the meniscus and read the appropriate part of the curve according to the liquid being measured.

Here, the student viewed the liquid from above eye level, so the line of sight was not perpendicular to the scale. That can produce a reading error due to viewing angle. Therefore, option A, parallax error, is correct. Selection bias concerns how subjects are chosen, publication bias concerns which results are reported, and sampling error concerns variation from studying part of a population; none describes this scale-reading problem.