Chapter 2: Measurement in Statistics - Dealing with Errors

This set of vocabulary flashcards covers types of measurement errors, the difference between accuracy and precision, and the calculations for absolute and relative error based on Chapter 2.2 of the Statistical Reasoning lecture.

Random errors

Errors that occur because of random and inherently unpredictable events in the measurement process.

Systematic errors

Errors that occur when there is a problem in the measurement system that affects all measurements in the same way.

Calibration error

A specific type of systematic error in which a scale’s measurements differ consistently from the true values.

Urban heat island effect

The phenomenon where urban areas tend to be warmer than their surrounding rural areas due to human activity, such as burning fuel and heat retention by pavement and masonry buildings.

Absolute error

A description of how far a claimed or measured value lies from the true value, calculated as: $\text{absolute error} = \text{claimed or measured value} - \text{true value}$

Relative error

A comparison of the size of the absolute error to the true value, often expressed as a percentage: $\text{relative error} = \frac{\text{absolute error}}{\text{true value}} \times 100\%$

Accuracy

A description of how closely a measurement approximates a true value; an accurate measurement is close to the true value, generally defined as having a small relative error.

Precision

A description of the amount of detail provided in a measurement.

Mars Climate Orbiter

A $\$160$ million NASA spacecraft lost in $1999$ because precise computer instructions in English units (pounds) were interpreted by software in metric units (kilograms), resulting in inaccurate data.

Significant digits

The digits in a number that were actually measured; all digits are considered significant except for zeros used solely to locate the decimal point.