Figure 1
From: Improving IQ measurement in intellectual disabilities using true deviation from population norms
Quantile-quantile (Q-Q) plot of the standardized and deviation intelligence quotient (IQ scores). Open circles represent the actual data points. The solid, diagonal red line is the reference line for the expected, normal distribution. The dotted lines represent the upper and lower bounds of the 95% confidence interval. EXIQ, Extended IQ; FSIQ, Full Scale IQ; NVIQ, Non-verbal IQ; VIQ, Verbal IQ. For the EXIQ plot, standard Full Scale IQ is shown above IQ = 40 for presentation and plotting purposes.