Sampling, randomization, and blindness
blindness
BLINDNESS
The sample size was calculated using the PASS 16 Power Analysis and Sample Size Software version 2018 (NCSS, LLC. Kaysville, Utah, USA, ncss.com/software/pass). The results indicated that the total sample size for the study has to be 338 subjects (169 patients in each group), with = 0.05 and power = 80%. To account for any dropouts, the sample size in each group was increased to 175 participants. The patient sequences were used for randomization. Patients with even numbers were assigned to the lavender group, while those with odd numbers were assigned to the control group. To ensure the validity of the study's findings, both groups were treated on different days to guarantee that the smell of lavender oil was completely removed from the clinics and waiting room. The following steps were taken to achieve blindness: 1) The patients, dentists who treated them, and evaluators who interviewed them to measure the study's variables were not informed about the study, so the vaporizers were placed as part of the clinic's and waiting room's equipment throughout the study's period, and 2) The investigators who reviewed the questionnaires and the statistician who analyzed the study's results only knew the study's groups as A and B.