Table 2.

The statistical description of structure indicators of three categories of concept maps

Cluster	N	V1	V2	V3	V4	V5	V6	V7	V8	V9	V10	V11	V12	V13	V14	V15	V16	V17	V18	V19
Cluster_0	225	0.90	0.97	0.82	1.07	0.90	0.19	0.84	0.93	1.02	1.41	0.80	0.70	0.57	0.75	0.72	0.54	0.72	0.70	0.07
Cluster_1	106	2.20	2.01	2.16	1.89	2.26	0.63	2.17	0.99	1.81	0.80	1.37	1.51	2.45	1.92	1.29	2.81	2.18	1.26	0.38
Cluster_2	28	4.98	4.45	4.93	3.58	5.19	1.41	4.99	1.01	3.16	0.58	1.87	2.49	8.08	4.55	1.75	10.26	5.55	1.76	0.35

N indicates the number of concept maps in this cluster