Related Experiment Video
Updated: Aug 7, 2026

Using Cholesky Decomposition to Explore Individual Differences in Longitudinal Relations between Reading Skills
Published on: September 17, 2019
Construction of multivariate centile charts for longitudinal measurements
1Department of Statistical Sciences, University of Cape Town, Rondebosch, South Africa.
Abstract:
Reference centiles are commonly used as a means of identifying whether some measure of interest on an individual lies within a 'normal' range. Individuals outside the range may be at risk for some problem outcome. The information needed to screen for problem outcomes in often multivariate in nature. We develop a multivariate approach to centile estimation which allows for updating of centiles based on the prior path of the individuals as well as adjustments to the centiles according to individual covariate values. It is also possible to consider several variables jointly as a screen for problem outcomes.
Related Concept Videos
Review and Preview
Percentiles are a type of fractile that partition data into...
Percentile
Boxplot
Modified Boxplots
However, the box plot does not tell the reader about outliers - values that lie far from the center of the data. We can modify the standard box and whisker plot to identify the outliers and visualize the actual spread of the data in a sample.
Initially, we calculate the adjusted...
Longitudinal Studies
Interpreting X̄ Charts
An x̄ chart plots the values of individual measurements over time against control limits calculated from historical data. The central line represents the process mean,...

