Physical activity and inactivity are two independent dimensions over which children aggregate into distinct behavioural profiles. Read my new article ‘Probabilistic principal component analysis to identify profiles of physical activity behaviours in the presence of non-ignorable missing data’ in the Journal of the Royal Statistical Society: Series C at http://onlinelibrary.wiley.com/doi/10.1111/rssc.12105/abstract.
Read my new article ‘Improved transformation-based quantile regression’ in the Canadian Journal of Statistics at http://onlinelibrary.wiley.com/doi/10.1002/cjs.11240/abstract!
A typical summary statistic for temporal trends is the average percent change (APC). The APC is estimated by using a generalized linear model, usually under the assumption of linearity on the logarithmic scale. A serious limitation of least-squares type estimators is their sensitivity to outliers. We propose a robust and easy-to-compute measure of the temporal trend based on the median of the rates (median percent change – MPC), rather than their mean, under the hypothesis of constant relative change.
An exciting one-day meeting organized by the RSS General Applications Section will take place in London on 29th May 2013. In the morning, the workshop will have a tutorial in quantile regression with hands-on using the R package quantreg. The research session in the afternoon will have three excellent speakers. Full programme and registration details here.