Which distribution best describes typical cost data?

• A. Left-skewed
• B. Bimodal
• C. Right-skewed
• D. Normal

Answer: (C)

Costs tend to cluster at lower values with a long tail to higher costs. In real-world cost data, most items are relatively inexpensive, but a few items incur very high costs, pulling the tail to the right. Since costs can’t be negative, that creates a right-skewed distribution, where the mean is pulled upward by the few large costs and the median sits closer to the bulk of the data.

This shape matters for analysis: the median often provides a more representative sense of typical cost, and analysts frequently use transformations or models suited for skewed data (for example, log-transformations or gamma-type models).

Left-skewed would imply a tail on the cheaper side, which isn’t typical for costs. A bimodal pattern would suggest two distinct cost groups rather than one gradual spread. A normal distribution would be symmetric, which doesn’t match the common skew toward higher-cost outliers.