Similarity	Concept
	Sign test
	Retrieval effectiveness
	E measure
	Effectiveness
	Statistical significance
	Measures of effectiveness
	Measurement of effectiveness
	Probabilistic retrieval
	Data retrieval systems
	Independence measurements

Similar pages

Similarity	Page	Snapshot
	178	document collections with different sets of queries then we can still use these measures to indicate which system satisfies the user more ...Significance tests Once we have our retrieval effectiveness figures we may wish to establish that the difference in effectiveness under two conditions is statistically significant ...Parametric tests are inappropriate because we do not know the form of the underlying distribution ...On the face of it non parametric tests might provide the answer ...
	176	conjoint structure ...The analysis is not limited to the two factors precision and recall,it could equally well be carried out for say the pair fallout and recall ...Presentation of experimental results In my discussion of micro,macro evaluation,and expected search length,various ways of averaging the effectiveness measure of the set of queries arose in a natural way ...In this section the discussion will be restricted to single number measures such as a normalised symmetric difference,normalised recall,etc ...The measurements we have therefore are Za Q 1,Za Q 2,...
	177	important that they are quoted alongside the distribution from which they are derived ...There are a number of ways of representing sets of Z values graphically ...A more convenient way of showing retrieval results of this kind is to plot them as cumulative frequency distributions,or as they are frequently called by statisticians empirical distribution functions ...I have emphasised the measurement of effectiveness from the point of view of the user ...