Experimental Design

Question	Answer
Hypothesis	"testable" statement that connects I.V. and D.V.
Independent Variable	deliberately changed; plotted on x-axis
Dependent Variable	measured variable; plotted on y-axis
Random Errors	caused by any factor that randomly effects the measurements of the I.V. ie. human errors
Identification of Random Errors:	amount of scatter can reflect amount of random errors. HIGH scatter = HIGH R.E. LOW scatter = LOW R.E.
REDUCTION of Random Errors:	increase in sample size allows averages to be calculated so the EFFECT of random errors can be MINIMISED.
ELIMINATION of Random Errors:	measurements CANNOT be perfect so R.E. can't be eliminated
Precision: (only for random errors)	(only for random errors) how well random errors are minimised. HIGH scatter {HIGH R.E}. = LOW PRECISION LOW scatter {LOW R.E.} = HIGH PRECISION
Systematic Errors	present when measured values differ CONSISTENTLY from the TRUE VALUE ie. faulty equipment, incorrect calibrations and experimental design
Identification of Random Errors:	g
REDUCTION of Random Errors:	h
Accuracy (only for systematic errors)	how close the results are to the TRUE VALUE
Experimental results can only be:	SUPPORTED or REFUTED {not proved}

Resource summary

	Created by R P over 9 years ago