MODULE 1 - STATISTICS OF ANALYTICAL MEASUREMENTS Flashcards
Two types of Analysis under Analytical Measurements
Qualitative Analysis and Quantitative Analysis
Repeating all the steps for each sample (or trial).
Replicate Analysis
Each data is represented as a dot or blob set on a scale on a horizontal line.
Dot/Blob Plots
The measurement results are grouped over a range and represented by a rectangle whose height gives the frequency of occurrence of the values covered.
Histogram
Most probable value, more reliable than any value in the set
Central Value
A measure of the spread of the values in the set
Dispersion
Indicates the closeness of the measurement to the true or accepted value and is expressed by the error
Accuracy
The closeness of results that have been obtained in exactly the same way
Precision
The difference between an individual result and the true value of the quantity being measured. Also expressed as a single value for a given measurement.
Error
Determinable and that presumably can either be avoided or corrected.
Systematic Errors
Caused by non-ideal instrument behavior, by faulty calibrations, or by use under inappropriate conditions.
Instrumental Errors
Result from the CARELESSNESS, INATTENTION or personal limitations of the analyst.
Personal Errors
Arise from non-ideal chemical or physical behavior of analytical systems.
Method Errors
Statistical fluctuations in the measured data.
Random Errors
The value of σ determines the spread of the curve. The greater the standard deviation, the more spread will be the curve.
Normal Distribution of Data
