[LON-CAPA-cvs] cvs: modules /gerd/correlpaper correlations.tex

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www		Mon Aug 14 08:11:51 2006 EDT

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  Causal relationships
  
  
Index: modules/gerd/correlpaper/correlations.tex
diff -u modules/gerd/correlpaper/correlations.tex:1.7 modules/gerd/correlpaper/correlations.tex:1.8
--- modules/gerd/correlpaper/correlations.tex:1.7	Wed Aug  9 14:43:39 2006
+++ modules/gerd/correlpaper/correlations.tex	Mon Aug 14 08:11:48 2006
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 The relative weakness of many of the expected correlations with the MPEX might indicate that maybe -- in spite of the efforts of the author -- the students did not take the MPEX very seriously or did not carefully read the statements. An argument for this possible explanation is that the overall scores of the students on the MPEX were low (Independence 42\%; Coherence 46\%; Concepts 48\%; Reality Link 55\%; Math Link 40\%; Effort 47\%). Also, students relatively frequently chose the answer "3" ("Neutral") on the MPEX Likert scale, which is by definition never correct --- answering that way could indicate true indifference, or confusion regarding the statement, or simply "don't care."
 
 By the same token, students appear to be taking the FCI more seriously, probably because it more closely matches the other (grade-relevant) assessments they encounter in the course, and students tend to based their relative value system regarding a subject area on the assessments used~\cite{lin}. The FCI seems to be fairly robust in ungraded settings, see for example Henderson~\cite{henderson}, who found only 0.5 points difference between graded and ungraded administration of the FCI --- the MPEX, which is never graded, may in fact be far less robust to the perception of  ``not counting."
+\subsection{Discussions Behavior versus FCI and Grade Performance}
+The study showed that there is a relatively strong correlation between solution-oriented discussion behavior (negative) and physics-oriented discussion behavior (positive) and the final FCI score. It is an interesting question whether the students learned physics better because of their more expert-like approach, or vice versa. In an attempt to answer this question, we are considering the FCI gain as a rough measure of how much physics the students {\it learned} (versus, for example, knew already). We also introduced a measure of discussion behavior gain by splitting the semester in half and calculating the the difference between the prominence of discussion behaviors in the first and the second half of the semester. We then calculated the following two correlations:
+\begin{itemize}
+\item FCI gain versus prominence of solution-oriented and physics-related postings
+\item FCI gain versus gain in prominence of solution-oriented and physics-related postings
+\end{itemize}
+
+As it turns out, the first correlations are significant, with $R=-0.44 [-0.65 - -0.18] (n=47)$ for FCI gain versus solution-oriented discussions, and $R=0.4 [0.13 - 0.62] (n=47)$ for FCI gain versus physics-related discussions. Such significant correlations do not occur for FCI gain versus any of the MPEX cluster scores.
+
+On the other hand, the correlations with discussion-gain are not significant: $0.24 [-0.05 -- 0.49] (n=47)$ for FCI gain versus gain in solution-oriented discussions, and $-0.12 [-0.39 -- 0.17] (n=47)$ for FCI gain versus gain in physics-related discussions. Note that these correlations have the opposite sign than expected, however, the confidence intervals include zero in both cases. When looking at the absolute values, the average gain in solution-oriented discussions between the two halves of the semester is 2.4\%, and the gain in physics-oriented discussions -0.3\% --- in other words, the students did not really change their discussion behavior over the course of the semester, and their discussion behavior does not improve co-measured with their increasing understanding of physics.
+
+Thus, the discussion behavior appears to be a property of the students that is almost constant over the course of the semester, probably reflective of their epistemology. A more expert-like approach that is reflected in more expert-like discussion behavior causes students to have higher learning gains in physics.
 
 \section{Conclusions}
 In this introductory calculus-based course, correlations between different performance and attitude indicators were found to be lower than expected. Student discussion behavior generally correlates more strongly with student performance (FCI, final exam, grade) than MPEX results. Particularly the prominence of solution-oriented and physics-related discussions correlate relatively strongly with the FCI.