In general, we find that students tend to confuse skew in an everyday sense (distribution with long tail) with skew in a strict statistical sense (distorted, incorrect). Research shows that this confusion is very frequently not resolved even after a student has completed an introductory course.

Student Notions

When presented with a prompt such as: "The researcher reported that the data were skewed. What does skewed mean in this context?", student responses have been summarized into the following categories (in this case, categories are exclusive):

  • Statistical Notions
    • Having a tail when graphed
    • Samples or results based on an experimental design flaw (Statistical Bias)
    • Vague references to distribution shape
    • Problems created by outliers
    • Data spread out; "All over the place"
  • Colloquial Notions
    • Incorrect, Different
    • Sudden change in direction
    • One-sided, lean in one direction (Colloquial Bias)


The following HILT activities have been designed to address student misconceptions regarding "Skew" and have research that suggests they improve student learning

Distorted Distributions