A population-based cross-sectional study aimed to examine sex differences in health-related quality of life (HRQoL) of older adults, and investigate whether the relation patterns between HRQoL and its correlates differed between sexes. A stratified proportional and representative sample included 802 volunteers, aged 60-79. HRQoL (36-item Short Form Health Survey), functional fitness (Senior Fitness Test), physical activity (PA) (Baecke questionnaire), demographic information and health features (questionnaires) were assessed. Men showed significantly higher HRQoL (P<0.001). Body mass index, body strength, aerobic endurance, PA, depressive symptoms, falls, and living alone were significantly related to HRQoL. With sex as moderator, these relations were not significant, except for PA (=0.12, P=0.004). A significant interaction of sex with PA on HRQoL (=0.08, P=0.037) was found, indicating that this relation was higher in men. A similar relation pattern was found for HRQoL physical component. HRQoL and its correlates differed between sexes, demanding a sex specific approach to promote HRQoL.

The present population-based cross-sectional study included a stratified proportional sample of volunteer older adults: 802 participants, 401 males and 401 females, from the Autonomous Region of Madeira, Portugal. Sex and age cohort served as stratification variables. Mean age of the overall sample was 69.8 years (SD=5.6), similarly distributed over the two subgroups (see Table 1). The sample size was determined following an a priori power analysis, which indicated that, to detect a small relation of r=0.15, with a two-tailed probability of 0.05 and a power of 0.99, the sample size would need to comprise 806 individuals.

Is t test analysis is used.???

1. Identify the null hypothesis and alternative hypotheses.
2. Address the type of data required and name three assumptions of the data that were met.
3. Discuss whether the finding in the study is statistically significant, in reference to the alpha-level and p-value.