Table 3. Random-effects intraclass correlation coefficient (ICC) for difficulty scores.
| Intraclass correlation | 95% Confidence interval | F Test with true value 0 | |||||
|---|---|---|---|---|---|---|---|
| Lower bound | Upper bound | Value | df1 | df2 | Sig | ||
| Single measures | .745 | .595 | .845 | 6,833 | 51 | 52 | .000 |
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