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Statistical methods for bioimpedance analysis


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Fig.1

The steps from the formulation of a hypothesis to the testing of the hypothesis by statistical methods.
The steps from the formulation of a hypothesis to the testing of the hypothesis by statistical methods.

Fig.2

Flowchart for selection of statistical method based on the type of study.
Flowchart for selection of statistical method based on the type of study.

List of important terms in the validation of new measurement technology along with the most usual and recommended ways of reporting. 1There are numerous different definitions in the literature, which can be inconsistent and confusing. These definitions provide one version with the aim of reducing ambiguity. 2Accuracy has previously been defined as the same as trueness only, but with ISO 5 725-1 [37], and reflected in the JCGM 200:2012 [19], the definition of accuracy has for the most changed to include both trueness and precision as given here. The old definition is still in use in some areas.

TermDefinition1Reported as
Measurement errorMeasured quantity value minus a reference quantity value [19]Systematic measurement error: Component of measurement error that in replicate measurements remains constant or varies in a predictable manner [19]Random measurement error: Component of measurement error that in replicate measurements varies in an unpredictable manner [19]Quantity on the same scale as the measurement scale, relative error, percentwise error, mean square error, root mean square error.Systematic measurement error: BiasRandom measurement error: Standard deviation, variance, coefficient of variation.
SensitivityThe sensitivity of a clinical test refers to the ability of the test to correctly identify those patients with the disease. [36].Eq. (1)A part of the ROC curve which shows the relation between sensitivity, specificity and the detection threshold.
SpecificityThe specificity of a clinical test refers to the ability of the test to correctly identify those patients without the disease. [36]Eq. (2)A part of the ROC curve which shows the relation between sensitivity, specificity and the detection threshold.
AgreementThe degree to which scores or ratings are identical [31]Continuous: Bland-Altman plotDiscrete: Percentage agreement
TruenessCloseness of agreement between the average value obtained from a large series of results of measurement and a true value [37].Bias (i.e. the difference between the mean of the measurements and the true value)
PrecisionCloseness of agreement between independent results of measurements obtained under stipulated conditions [37].Standard deviation, coefficient of variation
RepeatabilityPrecision determined under conditions where independent test results are obtained with the same method on identical test items in the same laboratory by the same operator using the same equipment within short intervals of time [37]Within-subject standard deviation [38]Repeatability coefficient [38]
ReproducibilityPrecision determined under conditions where test results are obtained with the same method on identical test items in different laboratories with different operators using different equipment [37]Standard deviation, coefficient of variation
Accuracy2Closeness of agreement between the result of a measurement and a true value (both trueness and precision) [37]Measurement accuracy: Closeness of agreement between a measured quantity and a true quantity value of a measurand [19]Bias (trueness) and standard deviation/ coefficient of variation (precision)Diagnostic accuracy: Sensitivity and specificitySensitivity and specificity corrected for prevalence as: (sensitivity)(prevalence)+(specificity)(1-prevalence) [39]
ReliabilityRatio of variability between subjects or objects to the total variability of all measurements in the sample [31]Intraclass correlation coefficientKappa statistics (categorical data)
eISSN:
1891-5469
Sprache:
Englisch
Zeitrahmen der Veröffentlichung:
Volume Open
Fachgebiete der Zeitschrift:
Technik, Bioingenieurwesen, Biomedizinische Elektronik, Biologie, Biophysik, Medizin, Biomedizinische Technik, Physik, Spektroskopie und Metrologie