Sample Size Limitation Clause Samples

Sample Size Limitation. Our study has a small sample size, with 81 records. To get a better association between Adherence and Depression, the number of independent variables was controlled based on Sample Size Caculation Formula(Peduzzi, Concato, Kemper, Holford, & ▇▇▇▇▇▇▇▇▇, 1996). Based on the work of ▇▇▇▇▇▇▇ et al., there is a formula to calculate sample size or variables. N = 10 k / p p is the smallest of the proportions of negative or positive cases in the population and k the number of covariates. To calculate reasonable number of independent variables of our study, we transformed the formula and calculated the number as 5. K=N*p/10=81*0.72/10= 5.6 (5 or 6 variables) (p=0.72 got from frequency of 1 or more missed appointments in last year in Table 1) In our study, the independent variables are Depression, Social Stigma, Education, Employment and Homelessness, which is accordance with reasonable number of independent variables.