Fig. 3
From: The effect of diet on serum 25-hydroxyvitamin D concentrations in dogs
Box and whiskers plot of serum 25(OH)D concentrations in dogs by dietary supplementation status. 214 dogs did not receive a supplement. The supplements used were salmon oil (n = 22), fish oil (n = 61), and fortified dog biscuits (n = 23). Open circles represent outliers that are more than 2.5 standard deviations from the group. Significantly different groups are represented by asterisk