10. Sources of error & their control or minimisation

what do Random errors effect?

Precision of measurement

What do Systematic errors effect

Accuracy of measurement

Features of a random error

• may change results in two directions→ either(both) positively or negatively

• error can be caused due to chance & unseeable

• occur when there are unknown or uncontrolled factors that affect measurement/variable

How can random errors be minimised?

• making more repeated measures

• calculating mean

• refining measurement method/technique

Factors of Systematic errors

• may change results in one directions→ either positively or negatively (consistently in the same direction)

• errors are foreseeable and preventable

• associated with a flaw in some aspect of the research design

How can systematic errors be minimised?

• detect and correct during statistical analysis in result

• prevent by adjusting research design

What are Human/Personal errors

Faults entirely sourced with the researcher

• mistakes

• miscalculations

• slip-ups

• observer error

Extraneous variables

• Any variable other than the IV that MAY cause change in DV

• can be difficult to conclude that change in DV was caused by IV

• can become confounding variable if not prevented

Confounding Variable

• Variable other than the IV that HAS or can not be separated and has a effect on the DV

• compromises internal validity

• can be difficult to conclude that change in DV was caused by IV