Bounds & Error Intervals

MathematicsAQAEdexcelGCSEUnit: Number
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The basics

The Hidden Range

The Hidden Range

If someone says they're "180 cm tall" (to nearest cm), they could actually be anywhere from 179.5 cm to 180.5 cm! When a value is rounded, there's always a hidden range of possible values - that's what bounds are about. This matters in engineering where precision is critical.
Bounds and accuracy diagram
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Key Terminology

Note: Lower bound uses ≤ (could be exactly this), Upper bound uses < (never reaches this)

Now try it yourself

Quiz · Question 1 of 14

A length is 240 cm to the nearest 10 cm. What is the lower bound of the length?

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