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For small numbers of trials (<30 per label), determination coefficients can become rather large even if there is no significant effect. To assess significance under the (robust) assumption of Gaussianity, determination coefficients may be converted into t-values according to
For small numbers of trials (<30 per label), determination coefficients can become rather large even if there is no significant effect. To assess significance under the (robust) assumption of Gaussianity, determination coefficients may be converted into t-values according to


<math>t^2=(n-2) frac{r^2}{1-r^2}</math>
<math>t^2=(n-2) \frac{r^2}{1-r^2}</math>


and used in a one-tailed t-test against the "no correlation" null hypothesis.
and used in a one-tailed t-test against the "no correlation" null hypothesis.


[[Category:Glossary]]
[[Category:Glossary]]

Revision as of 17:33, 16 January 2008

A glossary of general terms

r2 (Coefficient of Determination)

The statistical measure r2 calculates the fraction of the total signal variance that is accounted for by the task.

For small numbers of trials (<30 per label), determination coefficients can become rather large even if there is no significant effect. To assess significance under the (robust) assumption of Gaussianity, determination coefficients may be converted into t-values according to

t2=(n2)r21r2

and used in a one-tailed t-test against the "no correlation" null hypothesis.