Data analysis
In
Cronbach
indices of difficulty and discrimination have been calculated. Finally, an analysis of the
validity of the test was carried out, as well as a statistical analysis of the data contained
with the self-report instrument for its evaluation by the participants.
Results
Internal consistency
The Cronbach’s alpha coefficient of the overall score obtained by the participants
was .805, which is an acceptable consistency index (Nunnally, 1978) and much higher
than the minimum of .550, which is set for moderately broad constructs (Van DeVen &
Ferry, 1980) as is the case of reading comprehension.
Analysis of the items
The most relevant data obtained from the analysis of the items of the CLUni Test
are shown in table 2. In the second column, the indices of difficulty of the items are shown,
which have values between .185 and .908. According to the classification proposed by
Gil (2011, p.58), most of the items of the test (n = 24) would be included in the categories
of “very easy” and “easy” –with indices of difficulty greater than .55–. The rest of the
items could be considered “normal” (n = 2), “difficult” (n = 7) and “very difficult” (n =
3).
difficulty of these– when applying the test to students in lower grades, since, as evidenced
in a previous study (Felipe, 2015), the 4th year student's performance in an earlier version
of the CLUni Test is superior to the 1st. In the fourth column the indices of discrimination
of the items appear. Following, again, the classification proposed by Gil (2011, p. 61), 16
of the items discriminate very well (n =
4) or well (n = 12), 12 of the items discriminate little and 8 of the items must be improved
(n = 6) or lack utility to discriminate (n = 2). The last column shows the total alpha values
of the test associated with the deletion of each
item. These values demonstrate that the
elimination of some items would mean a minimum increase in the reliability index.
Table 2. Statistics obtained in the analysis of the items of the CLUni Test
Items
Index
of difficulty
Standard
Deviation
Index
of discrimination
Cronbach's
Alpha
if the element
has been
annulled
111