glossary

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A B C D E F G H I K L M N O P Q R S T U V W Y Z
  • DEFINITION

    [Variability] expresses quantitatively the extent to which scores in a group scatter about or cluster together.

    EXAMPLE OF USE

    When the emphasis is on the classroom climate, the focus of the examination would be the mean scores or ratings. Variations in the scores or ratings would be seen as differences in students’ perceptions of the classroom. When the emphasis is on the classroom culture, however, the focus would be primarily on the variability in the scores or ratings, and secondarily on the mean scores or ratings. Lower variability would indicate more common perceptions and, hence, the likely existence of a meaningful, workable classroom culture (Anderson, 2004: 57).

  • DEFINITION

    Variable costs are those whose amount varies according to output. Some of them are proportional to the volume of activity (for example, those relating to the consumption of non-durables); others may not be strictly proportional, for technical or financial reasons; for instance, the payment of overtime at rates higher than those applicable to normal hours of work. These costs increase in function of the level of output.

    EXAMPLE OF USE

    A system that sends printed documents or audio cassettes to students will generate variable costs, whereas a system that broadcasts radio and television programmes will be in the fixed costs category (Depover and Orivel, 2013: 54).

  • DEFINITION

    A measure of dispersion of a given distribution.

    EXAMPLE OF USE

    In New Zealand, Lauder et al. (1999), using a model that considers different variables relating to individual student characteristics, found that the variance between secondary schools corresponded to 16 per cent of the total variance in the results achieved by students in national examinations in mathematics and English. Variables linked to the school (including several measurements of composition) accounted for 40 per cent of this variance between schools. School effectiveness (including compositional effect) thus seems here to be statistically signifi cant and accounts for a little more than 6 per cent of the total variance in student scores (Dupriez, 2010: 57).

  • DEFINITION

    A language that is not formally recognized and that is used in informal contexts only (Bühmann and Trudell, 2008: 6).

    EXAMPLE OF USE

    However, some vernaculars current in rural areas have little or no literature, so offering literacy in them serves little purpose, unless provision is made for post-literacy activities, e.g. production of pamphlets, readers and rural newspaper in the vernacular (Atchoarena and Gasperini, 2003: 124).