Serum ferritin levels in thalassemia major patients treated with deferoxamine or deferiprone. The box stretches from the 25th to 75th percentile. The median is represented by a line across the box. The whiskers extend to the highest and lowest observed values that are lower than and higher than 1.5 times the interquartile range from the third and first quartile values. Outlying values beyond the whisker edges are excluded from the plot.