Many school tasks involving averages seem unrelated to any of the particular
interpretations we describe above. For example, finding the average of a set of
numbers out of context seems intended only to develop or test students’
computational abilities. Other school tasks explore formal properties of averages,
which we also would not view as directly related to particular interpretations. Such
tasks include those meant to demonstrate or assess the idea that (a) the mean of a set
of numbers is simply related to the sum of those numbers, (b) the mean is a balance
point and the median a partition that divides the cases into two equal-sized groups,8
(c) the mean and median lie somewhere within the range of the set of scores, and (d)
the mean or median need not correspond to the value of an actual observation. In
their longitudinal study of the development of young students’ understandings of
average, Watson and Moritz (2000) focused in particular on these relations, asking
students, for example, how the mean number of children per family could possibly
be 2.3 rather than a whole number. We consider most of the properties enumerated
by Strauss and Bichler (1988, p. 66) to be formal relations of this sort. We are not
arguing that these are unimportant or trivial ideas, but rather that they are usually not
tied to particular interpretations of averages.
Many school tasks involving averages seem unrelated to any of the particular
interpretations we describe above. For example, finding the average of a set of
numbers out of context seems intended only to develop or test students’
computational abilities. Other school tasks explore formal properties of averages,
which we also would not view as directly related to particular interpretations. Such
tasks include those meant to demonstrate or assess the idea that (a) the mean of a set
of numbers is simply related to the sum of those numbers, (b) the mean is a balance
point and the median a partition that divides the cases into two equal-sized groups,8
(c) the mean and median lie somewhere within the range of the set of scores, and (d)
the mean or median need not correspond to the value of an actual observation. In
their longitudinal study of the development of young students’ understandings of
average, Watson and Moritz (2000) focused in particular on these relations, asking
students, for example, how the mean number of children per family could possibly
be 2.3 rather than a whole number. We consider most of the properties enumerated
by Strauss and Bichler (1988, p. 66) to be formal relations of this sort. We are not
arguing that these are unimportant or trivial ideas, but rather that they are usually not
tied to particular interpretations of averages.
การแปล กรุณารอสักครู่..
