. 2014 Mar-Apr;40(2):119–127. doi: 10.1590/S1806-37132014000200004

Table 2. Frequency of nebulizer contamination before and after the standardized instruction had been given (n = 40).

Nebulizer contamination	Before the instruction^a	After the instruction^a	p*	p after correction by the time interval between assessments**
Any part	23 (57.5)	10 (25.0)	0.002	0.001
Mouthpiece	16 (40.0)	7 (17.5)	0.022	0.011
Cup	19 (47.5)	5 (12.5)	< 0.001	< 0.001

Values expressed as n (%)

McNemar's test

^**

Generalized estimating equations model