Method of Evaluation

Question 1

Known as the foundation for monitoring performance

Answer 1

Quality Control

Question 2

Sources of Analytic Variability

Answer 2

Operator technique
Instrument differences
Test accessories
Contamination

Question 3

Measures of Center

Answer 3

Mean
Median
Mode

Question 4

Obtained through dividing the sum of the data points (Σ) by the total number of data points (n)

Answer 4

Mean

Question 5

Rarely used, but often used to describe data that seemed to have two centers (bimodal)

Answer 5

Mode

Question 6

Measures of Spread

Answer 6

Range
Standard Deviation
Coefficient of Variation

Question 7

The difference between the largest value and smallest value in a dataset

Answer 7

Range

Question 8

Represents the “average” distance from the center of the data (the mean) and every value in the dataset

Answer 8

Standard Deviation

Question 9

Most frequently used measure of variation

Answer 9

Standard Deviation

Question 10

Compares SDs with different units

Answer 10

Coefficient of Variation

Question 11

Bell-shaped curve/Normal distribution curve/Normal frequency curve

Answer 11

Gaussian Curve

Question 11

Describe the 68–95–99 Rule of Gaussian distribution

Answer 11

≈68% of the data fall between ±1 SD from the mean
≈95% of the data fall between±2 SDs from the mean
≈99% fall between ±3 SDs from the mean

Question 12

Describe as the difference between test and reference method results

Answer 12

Errors

Question 13

Type of error that is present in all measurements and can be either positive or negative

Answer 13

Random Error

Question 14

Error that occur due to chance

Answer 14

Random Error

Question 15

Factors contributing to random error

Answer 15

Instrument
Operator
Reagent
Environmental variations

(pipetting error, mislabeling in samples, temperature of analyzer, and improper mixing of sample or reagent)

Question 16

Error that can influence the observations consistently in one direction

Answer 16

Systemic Error

Question 17

Corrective measures for systemic errors

Answer 17

Check on equipment/ machines
Check reagents
Check quality control materials
Check standard solutions
Review standard operating procedures

Question 18

Factors contributing to systemic error

Answer 18

Calibration problems
Deterioration of reagents and control materials
Improperly made standard solutions
Contaminated solutions
Unstable and inadequate reagent blanks
Leaky ion selective electrode
Poorly written procedures.

Question 19

Error that exists when there is a continual difference between the test method and the comparative method values, regardless of the concentration

Answer 19

Constant Systematic Error

Question 20

Cause of systematic constant error

Answer 20

Interference or contamination

Question 20

Error that exists when the differences between the test method and the comparative method values are proportional to the analyte concentration

Answer 20

Proportional Error

Question 21

Cause of proportional error

Answer 21

Poor recovery of analyte during an analysis