Researchers have suggested that sleep apnoea (the tendency to occasionally stop breathing when asleep) may worsen the effects of allergen-induced asthma. To investigate this possibility, Johnson and colleagues (2015), compared two groups of rats, a normal healthy non-allergic group, and a second group that were mildly allergic to ovalbumin. They subjected these rats to one of two treatments – 1) a 10-minute period of induced hypoxia (oxygen down to 10% of the air), representing the kind of temporary hypoxia that sufferers of sleep apnoea may be subjected to, and 2) a control (normal air) group. They then compared the respiratory function of both groups in these two treatments by using a two-factor ANOVA. (Questions are on the next page).

Researchers have suggested that sleep apnoea (the tendency to occasionally stop breathing when asleep) may worsen the effects of allergen-induced asthma. To investigate this possibility, Johnson and colleagues (2015), compared two groups of rats, a normal healthy non-allergic group, and a second group that were mildly allergic to ovalbumin. They subjected these rats to one of two treatments – 1) a 10-minute period of induced hypoxia (oxygen down to 10% of the air), representing the kind of temporary hypoxia that sufferers of sleep apnoea may be subjected to, and 2) a control (normal air) group. They then compared the respiratory function of both groups in these two treatments by using a two-factor ANOVA. (Questions are on the next page).

Source	df	F	P
Rat type	1	21.88	<0.0001
Oxygen treatment	1	141.13	<0.0001
Rat type x oxygen treatment	1	15.68	<0.001
Residual	36