Which practice should you apply when reading a chart and numbers are rounded?

• A. Rounding always preserves the exact value.
• B. Rounding never affects interpretation.
• C. Potential loss of precision; check if rounding affects significance.
• D. Rounding reduces dataset size.

Answer: (C)

Rounding introduces a loss of precision, so when you read a chart you must consider whether that rounding could change how you interpret the numbers. If the differences between values are small—smaller than the rounding unit—the apparent gap might vanish or look bigger than it truly is. This matters for judging significance: a difference that seems important may actually be just a result of rounding, or vice versa. So the key practice is to recognize the potential loss of precision and assess whether rounding affects whether the observed differences are meaningful.

Rounding doesn’t preserve the exact value, so the first point is false. It can influence interpretation, so the second point is false. Rounding changes precision, not the amount of data, so the idea that it reduces dataset size isn’t the main issue.