STATISTICAL CONCEPTS in QUALITY CONTROL Flashcards

1
Q

A statement of the extent of random variation in any series of measurement

A

STANDARD DEVIATION

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2
Q

A measure of the distribution of values around the mean

A

STANDARD DEVIATION

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3
Q

Square of the standard deviation

A

VARIANCE

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4
Q

Used to detect significant differences between groups of data

A

VARIANCE

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5
Q

Determine contributions of various factors to the total variation

A

VARIANCE

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6
Q

Percentile expression of the mean

A

COEFFICIENT OF VARIATION

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7
Q

Measure of the relative magnitude of variability

A

COEFFICIENT OF VARIATION

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8
Q

CV = s (100)/X

A

COEFFICIENT OF VARIATION

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9
Q

Reported values do not fall along the line of slope when graphed

A

Analytical Bias

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10
Q

Reported lab results do not correspond to the correct value

A

Analytical Bias

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11
Q

Problem on Accuracy (Bias) = ____________

A

Systematic error

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12
Q

Refers to laboratory analyses that are subject to imprecision

A

Random Analytical Variability

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13
Q

Problem on Precision (CV) = _____________

A

Random Error

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14
Q

can be systematic or personnel-related

A

Errors

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15
Q

Sources cannot be completely controlled or identified

A

RANDOM ERRORS

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16
Q

Increase the extent of variability of results

A

RANDOM ERRORS

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17
Q

Displace the mean value on one direction (may be up or down), but do NOT affect the overall variability as shown by the SD value

A

SYSTEMATIC ERRORS

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18
Q

decomposition of reagents during storage

A

Aging phenomena

19
Q

Series of values on the control chart that continue to increase or decrease for at least a period of six (6) consecutive days

A

TREND

20
Q

Values that distribute themselves on one side of the mean for at least six (6) consecutive days

A

SHIFT

21
Q

Q.C. procedures performed on a daily basis within individual laboratories

A

INTRALABORATORY / INTERNAL

22
Q

Monitoring is carried out using:

A

o Levey – Jennings Chart
o Westgard Multi-rule Chart
o CUSUM Technique

23
Q

Performed on a less frequent basis (e.g. 3x a year) to compare performance b/w or among laboratories

A

INTERLABORATORY / EXTERNAL

24
Q

graphical representations that display the control observation as a function or time

A

QUALITY CONTROL CHARTS

25
Q

Control results are plotted on the Y-axis (ordinate) vs time on the X-axis (abscissa)

A

LEVEY – JENNINGS CHART

26
Q

a control value that goes beyond ±2SD

A

Outlier

27
Q

 Uses a series of control rules for interpreting data
 False rejection is kept low

A
  1. WESTGARD MULTIRULE CHART
28
Q

 Error detection is improved
 Analyse samples of the control material by the analytical method to be evaluated (at least 20 days)

A

WESTGARD MULTIRULE CHART

29
Q

seeks to identify, measure, and eliminate the large gaps of inefficiency in a process

A

SIX SIGMA

30
Q

Provides a display of the differences b/w the observed values & the expected mean

A

CUMULATIVE SUM (CUSUM) CHART

31
Q

Used to monitor small shifts in the process mean.

A

CUMULATIVE SUM (CUSUM) CHART

32
Q

Obtain the CUSUM by adding the difference (value from the mean) to the CUSUM of the previous
differences

A

CUMULATIVE SUM (CUSUM) CHART

33
Q

Under the interpretation od CUSUM chart. If it is a steep slope, it suggests that?

A

presence of SE (Out of Control)

34
Q

found in clinical Laboratories with microcomputer Q.C. programs

A

DECISION LIMIT CUSUM

35
Q

Laboratory’s observed mean for material A (Y-axis) compared to the observed mean for material B
(X-axis)

A

YOUDEN PLOT / SCATTER DIAGRAM

36
Q

Information about the nature of the SE can be obtained when two diff. control materials have been analyzed

A

YOUDEN PLOT / SCATTER DIAGRAM

37
Q

Presents information in an efficient, graphical format

A

CHECK SHEET

38
Q

Accomplished with a simple listing of items

A

CHECK SHEET

39
Q

Used to identify factors that have the greatest cumulative effect on the system

A

PARETO CHART

40
Q

Used to associate multiple possible causes with a single effect

A
  • Ishikawa or Fish bone diagram
41
Q

Pictorial representations of a process

A

Flow chart

42
Q
  • Used in identifying where errors are likely to be found in the system
A

Flow chart

43
Q

Provides a simple, graphical view of accumulated data, including its dispersion & central tendency

A

HISTOGRAM

44
Q

Ease of construction

A

HISTOGRAM