Figure 1.

Histograms of FIQ and FIQR showing distributions of total scores. (a) The distribution profile of the total Revised Fibromyalgia Impact Questionnaire (FIQR) scores in 202 fibromyalgia (FM) patients. (b) The distribution profile of the total Fibromyalgia Impact Questionnaire (FIQ) scores. There is a slight negative skewness for both distributions. The FIQR Shapiro-Wilk skewness coefficient (W) is 0.978, and the FIQ Shapiro-Wilk skewness coefficient (W) is 0.980.

Bennett et al. Arthritis Research & Therapy 2009 11:R120   doi:10.1186/ar2783
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