We generated probabilities for different groups of students participating by using the model to create a logit for that probability and then converting the logit to a probability using Eq. 8. Level 1 equations begin{array}{*{20}l} {text{Probability}}({text{Participation}}_{ijk} = 1|pi_{jk}) = phi_{ijk} end{array} (1).
The sample was divided into two groups in order to verify achievement of the objectives of the study: an intervention group which participated by using and implementing the Evalsoft tool (73.6 % of the sample) and a non-intervention group which was given traditional education with no specific use of virtual campus except for collecting material (26.4 %).
Pupils and parents were invited to participate by letter, using databases of schools to identify potential participants.
Students were not made aware of the study during their rotation and were invited to participate by writing using end of rotation questionnaires at the end of their CTU rotation.
A random sample of 75 GPs, from the list of all GPs practising in the canton, was invited to participate by post, using simple random sampling, in order to include 25 GPs in the study (expected participation rate: 33%).
19, 20 The GÅS-SNAC population, which comprised 2,931 men and women (44%/56%, respectively) from nine age cohorts – 60, 66, 72, 78, 81, 84, 87, 90, and 93 years of age – was randomized from five urban and rural municipalities and invited to participate by letter using the National Municipality Registry.
However, one participant commented that without formal appeals mechanisms, some stakeholders participated unfairly by using a 'squeaky wheel' approach.
Therefore, HLA simulations are not restricted to be participated solely by using desktop computers with cable connections.
More precisely, we imputed missing variables contained in the student background datafile for Tunisia (one of the TIMSS 2007 participating countries), by using Van Buuren, Boshuizen, and Knook's (SM 18 681-694,1999) chained equations approach.
