The Role of Visual Features in Text-Based CAPTCHAs: An fNIRS Study for Usable Security

Table 3

Detected significant changes in mean values (tests of within-subjects effects).

Method				Type III SS	df	MS	F		Partial η2
HbO	o1	Line wave rotation	Sphericity assumed	1.657	4	0.414	3.892	0.006	0.170
	o11	Line wave rotation	Sphericity assumed	1.410	4	0.352	3.427	0.012	0.146
	o12	Line wave rotation	Sphericity assumed	1.044	4	0.261	2.587	0.044	0.126
	o13	Line wave rotation	Sphericity assumed	1.039	4	0.260	2.554	0.046	0.118
	o16	Wave rotation	Sphericity assumed	0.742	2	0.371	3.686	0.034	0.156
		Line wave rotation	Sphericity assumed	1.092	4	0.273	3.176	0.018	0.137
	o2	Line wave rotation	Sphericity assumed	1.203	4	0.301	2.736	0.034	0.120
	o3	Line wave rotation	Sphericity assumed	1.115	4	0.279	2.588	0.043	0.115
	o4	Line wave rotation	Sphericity assumed	1.603	4	0.401	3.730	0.008	0.172
HbR	o6	Wave rotation	Sphericity assumed	0.206	2	0.103	3.712	0.034	0.171
HbT	o1	Line wave rotation	Sphericity assumed	1.665	4	0.416	4.024	0.005	0.175
	o10	Line rotation	Sphericity assumed	2.098	2	1.049	4.180	0.023	0.180
	o12	Line wave rotation	Sphericity assumed	1.156	4	0.289	2.542	0.047	0.124
	o14	Line wave rotation	Sphericity assumed	1.172	4	0.293	2.664	0.040	0.143
	o16	Line wave rotation	Sphericity assumed	1.091	4	0.273	3.185	0.018	0.137
	o2	Line wave rotation	Sphericity assumed	1.150	4	0.287	2.624	0.041	0.116
	o4	Line wave rotation	Sphericity assumed	1.285	4	0.321	2.663	0.039	0.129
	o8	Line rotation	Sphericity assumed	2.027	2	1.013	3.586	0.038	0.166
Oxy	o1	Line wave rotation	Sphericity assumed	1.827	4	0.457	3.425	0.013	0.153
	o10	Line wave rotation	Sphericity assumed	1.517	4	0.379	2.850	0.029	0.130
	o11	Line wave rotation	Sphericity assumed	2.120	4	0.530	3.554	0.010	0.151
	o13	Line wave rotation	Sphericity assumed	1.631	4	0.408	2.533	0.047	0.118
	o3	Line wave rotation	Sphericity assumed	2.029	4	0.507	3.022	0.022	0.131
	o4	Line wave rotation	Sphericity assumed	2.004	4	0.501	4.108	0.005	0.186
	o9	Line wave rotation	Sphericity assumed	1.884	4	0.471	3.464	0.012	0.148