Author note — to cover

Construct and read back-to-back stem-and-leaf diagrams: shared stems, left side read outwards, a key for each side. Questions extract the median and range of each side and make one comparison in context. Full comparison technique pairing average with spread lives on the Interpretation topic. Both tiers. (S4)

Introduction

—coming soon—

Practice and continue

Practice

Back-to-back stem-and-leaf diagrams

Two data sets sharing one set of stems, with left-hand leaves read outwards.

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Frequency polygons

Plotting each class frequency at its midpoint, not at the class boundaries.