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numbers and algebraic expressions
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elements of statistics
kropki game

Absolute error of measurement: Δx = |x - x_z|, x -- exact (real) value, x_z -- measured (approximated) value. Absolute error show how much the measured value is different from the real value. Relative error of measurement: δ = (Δx / x) * 100%. Δx -- absolute error, x -- exact (real) value. Relative error show how many percent the measured value is different from the real value. Examples.