Predicting the difficulty of EFL reading comprehension tests based on linguistic indices

Table 2 Summary of the descriptive statistics

Variables	Min.	Max.	Mean	SD	N
Observed difficulty	0.50	0.92	0.77	0.11	63
Narrativity	− 2.57	1.47	− 1.12	0.72	63
Syntactic simplicity	− 2.44	1.00	− 0.66	0.83	63
Word concreteness	− 1.79	2.37	0.31	1.02	63
Referential cohesion	− 2.33	2.59	− 0.09	0.96	63
Deep cohesion	− 1.63	4.37	0.29	1.10	63