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.

Explain t test

what is null hypothesis and alternative hypothesis

Address the type of data required and name three assumptions of the data that were met.

Discuss whether the finding in the study is statistically significant, in reference to the alpha-level and p-value.