L3 - Data Quality

ERROR

• defined as a deviation from the absolute value or from the true average of a large number of results. 

SYSTEMATIC ERROR or INDETERMINATE ERROR

ERRORS can be classified as?

DETERMINATE ERRORS

SYSTEMATIC ERROR also known as

SYSTEMATIC ERROR

errors that are reproducible and can be discovered and corrected

• INSTRUMENTAL Error -

• METHOD Error

• PERSONAL Error

TYPES of SYSTEMATIC ERRORS

INSTRUMENTAL ERROR 

Failure to calibrate, degradation of parts in the instrument, power fluctuations, variation in temperature.

METHOD ERRORS 

errors due to no ideal physical or chemical behaviour, completeness and speed of reaction, interfering side reactions, sampling problems.

PERSONAL ERRORS 

occur where measurements require judgment, result from prejudice, color acuity problems, or negligence to follow proper procedures

INDETERMINATE ERRORS

RANDOM ERRORS also known

RANDOM ERRORS

• are observed by the same analyst when the successive measurements are made with the same identical conditions. 

• appear as slight variations in successive measurements due to causes that the analyst can not control.

normal frequency curve

RANDOM ERRORS plot of indeterminate error would show a

PARALLEL DETERMINATIONS.

MINIMIZATION of ERRORS

By running the?

blank solution

defined as the solution by omitting the sample addition.

• CALIBRATION

MINIMIZATION of ERRORS

• Proper ____ of the glass ware, pipettes, burettes, weights, balances, instruments, etc. 

VALIDATION 

• is establishing DOCUMENTED EVIDENCE which provides a high degree of assurance that a specific process, method, system, activity or equipment consistently produce a product meeting its predetermined specification

• DOCUMENTED EVIDENCE

VALIDATION 

• is establishing _____ which provides a high degree of assurance that a specific process, method, system, activity or equipment consistently produce a product meeting its predetermined specification

ACCURACY 

pertains to agreement of an experimental results with true value

PRECISION 

is the measure of reproducibility of data within a series of results

MEAN

• measure of central tendency 

RANGE

difference between largest/smallest observations in a set of data 

AVERAGE DEVIATION

measures the difference of the actual values with the mean value 

RELATIVE AVERAGE DEVIATION 

determined by dividing the average deviation by the mean 

VARIANCE 

sum of squares difference of the actual values with the mean value/total number of samples 

STANDARD DEVIATION 

square root of variance

PERCENTAGE RELATIVE ERROR

measure of the ACCURACY of the method

ACCURACY

PERCENTAGE RELATIVE ERROR measure of the ___ of the method

ACCURATE and PRECISE.

Results should be ___ and ____

68%

WHAT % of the values should fall within one standard deviation

95%

WHAT % should fall within two standard deviations of the mean