Wk 1- Biomed Skills- Measurement and Error Flashcards
What is data?
Items of info
Are measured or observed
2 Broad categories of data
Quantitative
Qualitative
Types of quantitative data
Continuous (scale)
Discontinuous (Whole no.s, no order)
Ranked (by magnitude or occurrence). Measured against a scale
Types of qualitative data
Nominal (no order)
Categorical
What should be considered when planning an exp.?
Data needed
How to collectanalyse data
Precision
Closeness of repeated measurements
Accuracy
How close data is to true values
Validity
How well results reflect concept trying to be measured
Reliability
Precision + accuracy
Same results if repeated?
2 types of reliability
Test-retest (same person)
inter-observer (dif people)
Bias
Systemic (non-random) distortion of results
Sources of bias
Faulty or uncalibrated equipt.
Experimental manipulation
Subjective or personal bias
How is bias minimised?
Standardised procedures and calibration
Blind exp.
Trials using dif methods of measuring
+ and - data presented
Sources of measurement error
Technical error
Bio var
Sources of technical factors
Operator error (intra and inter)
Incorrect reading of results
Non-standardised procedures
Poor sampling method
Equipt. error (limitations or change in measurements over time)
Technical error of measurement
Precision of repeated measurements
(High TEM = low precision)
TEM equation
TEM = √ Σd² / 2n
d= X1 - X2
n= no. of subjects
Relative TEM equation
(TEM / ((M1 + M2) / 2)) * 100
M= Mean
Standard deviation
How much measurements vary from mean
