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Fig. 6 | BMC Medical Research Methodology

Fig. 6

From: Why item response theory should be used for longitudinal questionnaire data analysis in medical research

Fig. 6

Sum-score distributions. Histograms with the sum-score distribution for the latent variable ‘state anxiety’ on the three measurement occasions in the AGHLS cohort. The skewness of the sum-score distributions was 1.02; 0.99; and 1.18 on the first, second, and third measurement occasion from left to right, and 443, 338, and 126 participants were included respectively

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