2. QC Flashcards
variable that can assume any value within the range of scores that define the limits of the variable
continuous
Assume a defined set of integers
discrete
Values fall into unordered categories or classes
nominal/categorical
Numbers that are discrete and ordered (ranked)
ordinal data
Mean, range, variability, and distribution of a data set
descriptive statistics
Concerned with the relationship among different sets or samples of data
inferential statistics
The closeness of the agreement between the measured value of an analyte to its “true” value.
accuracy
procedures used to measure accuracy
Comparison of methods
Testing proficiency samples
Recovery experiments
calculate system’s bias
known value - result
describe recovery experiment
small amount of concentrtated analyte is spiked into patient sample
percent recovery is found
percent recovery
% recovery = (spiked result - baseline result)/analyte added
A systematic error in a method or error caused by some artifact or idiosyncrasy of the measuring system.
Presence of nonrandom events.
bias
Ability to produce the same value for replicate measurements of the same sample.
precision
how to measure precision
Validated by running the same sample multiple times
Closeness of agreement between results of successive measurements carried out under the same conditions
within-run analysis
Closeness of agreement between results of measurements performed under changed conditions of measurements
between-run analysis
normal curve around QC mean reflects that…
most of your results fall around the predictive value, but some do not.
SD is a measure of…
dispersion
A range around an experimentally determined statistic that has a known probability of including the true parameter
confidence interval
A statistical measure of the dispersion of data points around the mean
Reflection of precision
Measure of variability
Coeffecient of variation
statistical equalizer
CV
variance =
s^2 = 𝛴(x - mean)^2
SD to CV
1
2
3
68%
95%
99%
standard deviation