Table 5.

Comparison of mean scores of knowledge about search operators in intervention and control groups

Operators	Groups	Pre test	Post test	Mean difference	Statistic t* and p
		M ± SD	M ± SD
AND	Intervention	0.16 ± 0.06	0.96 ± 0.03	0.80	t = −9.40 p < 0.001
	Control	0.20 ± 0.08	0.13 ± 0.06	−0.07	t = 1.00 p = 0.32
	Statistic t** and p	t = −44 p = 0.66	t = 11.77 p < 0.001
OR	Intervention	0.19 ± 0.07	0.96 ± 0.03	0.77	t = −8.66 p < 0.001
	Control	0.21 ± 0.08	0.13 ± 0.06	−0.08	t = 1.00 p = 0.32
	Statistic t** and p	t = −0.21 p = 0.83	t = 11.77 p < 0.001
NOT	Intervention	0.12 ± 0.06	0.93 ± 0.04	0.80	t = −9.40 p < 0.001
	Control	0.12 ± 0.06	0.06 ± 0.04	−0.06	t = 1.00 p = 0.32
	Statistic t** and p	t = 0.04 p = 0.96	t = 13.47 p < 0.001
Proximity operator	Intervention	0.12 ± 0.06	0.87 ± 0.06	0.74	t = −8.03 p < 0.001
	Control	0.10 ± 0.03	0.08 ± 0.05	−0.02	t = 0.02 p = 0.80
	Statistic t** and p	t = 2.10 p = 0.04	t = 14.23 p < 0.001
Total	Intervention	0.61 ± 0.23	3.74 ± 0.14	3.12	t = −9.86 p < 0.001
	Control	0.56 ± 0.21	0.33 ± 0.12	−0.23	t = 0.01 p = 0.84
	Statistic t** and p	t = −0.14 p = 0.88	t = 17.37 p < 0.001

*Paired t-test

**Independent t-test