Which graph is preferred over box-plots or dot-plots for visualizing reference data?

• A. Box-plots
• B. Scatter plots
• C. Histograms
• D. Dot-plots

Answer: (C)

Visualizing reference data is most informative when you can see the actual distribution shape, how spread out the values are, and whether there are skewness or multiple peaks. A histogram provides this by showing how often values fall into each value range, making patterns like symmetry, skew, or multimodality immediately apparent. Box-plots give only a summary (median, quartiles, and extremes), which can hide important distribution details, and dot-plots, while showing individual points, become crowded with larger reference data and still don’t convey the overall distribution as clearly as a histogram. So, a histogram is preferred because it communicates the distribution characteristics of the reference data most effectively, helping you assess where a new value falls within the reference distribution.