For those who exercised less than the recommended amount, a one unit increase in the perceived stress scale mean item response was related to a 15-fold increase in the odds of having short telomeres (B0 = −4.27, Bstress = 2.74, SEstress = 1.09, OR = 15.48, p = .01), controlling for mean-centered education and BMI.
Sub-scale scores were calculated using the mean item response.
ANALYSES: Analyses include evaluation of data quality (eg, logic and range checking, spread of response distribution within an item), descriptive statistics (eg, frequencies, means), item response theory model assumptions (unidimensionality, local independence, monotonicity), model fit, differential item functioning, and item calibration for banking.
The full scaling range (0 5) for all 32 items was used (mean item responses ranged from 2.04±1.5 for "being breathlessness never interrupts my conversations" to 3.88±1.3 for "when I walk up one flight of stairs I am not breathless").
Data quality was assessed by mean, median, item response, missing values, floor and ceiling effects, internal consistency (Cronbach's alpha and average inter-item correlation), item-rest correlations.
Scale scores were computed as the mean numeric item response with higher scores indicating higher levels of safety compliance and participation.
ATS system is equipped with an emotional agent inspired by the psycho-pedagogical researches of control-value theory that try to estimate the student's emotion during a reusable learning object (RLO), having as a stimulus the ability evaluated by means of item response theory.
Binary item disengagement indicators were created by means of item response time thresholds.
By means of item response theory, the CBA is empirically evaluated and tested for construct validity in a third step (Quellmalz et al. 2012).
The MIAr was then submitted to a new evaluation using the Rasch model, in order to verify evidences of validity by means of item response process (Primi et al. 2009).
IROS characteristics were investigated by means of Item Response Theory models.
