Figure 1
From: Infantile zinc deficiency: Association with autism spectrum disorders
Histogram of logarithmic zinc concentration in autistic children (N = 1,967).
The histogram of scalp hair zinc concentrations for 1,967 children (1,553 males and 414 females) aged 0–15 year-old is shown in the logarithm. The numbers on the abscissa indicate the logarithms of scalp hair zinc concentrations (ng/g hair: ppb). The height of each rectangle represents the frequency in the class interval in logarithmic hair zinc level. The dotted vertical line represents the −2S.D. (standard deviation) level of the control reference range of hair zinc concentrations.
