Table 1.

Linear regression model predicting item difficulty from the radicals (test Version 1).

Predictor	β	SE	t	p
(Intercept)	1.104	0.110	9.997	<0.001***
Melody length	0.494	0.098	5.034	<0.001***
Contour violation	−0.377	0.156	−2.411	0.031*
Tonality violation	−0.737	0.156	−4.716	<0.001***
Melody length * contour violation	0.319	0.113	2.814	0.015*
Melody length * tonality violation	−0.282	0.113	−2.489	0.027*
Contour violation * tonality violation	0.269	0.221	1.216	0.246

Note. *p < 0.05. ***p < 0.001. Regression coefficients are standardised.