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Linear Mixed Model Sample Size Calculations

This post outlines a Shiny app to calculate the required sample size for a two-group linear mixed model. It uses the power.mmrm function from the longpower package (see Lu, Luo, & Chen, 2008, for more information). The input is simplified, whereby users are limited to five time-points, the correlation matrix is a compound symmetry correlation … Continue reading Linear Mixed Model Sample Size Calculations

SF-12 v2 scoring using Australian population weights

This brief post provides the R syntax to calculate SF-12 v2 scores using Australian population weights. The population weights are derived from: Hawthorne, G., Osborne, R., Taylor, A., & Sansoni, J. (2007). The SF36 Version 2: critical analyses of population weights, scoring algorithms and population norms. Quality of Life Research, 16(4), 661-673. doi: 10.1007/s11136-006-9154-4 Please … Continue reading SF-12 v2 scoring using Australian population weights