Measurement digits have different importance {significant figure}| {significant digit}. Zeroes to left of left-most non-zero digit are not meaningful. If number has no decimal point, zeroes to right of right-most non-zero digit are not meaningful. If number has decimal point, zeroes to right of right-most non-zero digit are meaningful. Zeroes between non-zero digits are meaningful.
instruments
Number of significant digits is number of measured digits, including estimated digit.
products
For calculation results, number of significant digits is smallest measured number of significant digits. Multiplying or dividing measurements must maintain number of meaningful digits.
Analyses have number of significant figures {accuracy}|.
Analog-instrument sensitivity {precision}| is tenth of distance between marks. For example, ruler with millimeter markings has precision tenth of millimeter. Digital-instrument precision is displayed numbers.
Quantitative analyses have variability range. Repeated measurements must have similar results {reproducibility}|. If repeated measurement results in significantly different values, results are not reproducible.
Quantitative analyses can detect substance from among other materials {selectivity, measurement}|. For example, instruments detect one frequency or smaller or larger frequency range.
Quantitative analyses have minimum detectable amount {sensitivity, measurement}|. For example, instruments detect intensity threshold.
Precise-measurement technique {nulling}| cancels unknown values using known standard or sensed values using expected values. Nulling methods do not require apparatus to be linear.
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Date Modified: 2022.0225