Here is the design of a clinical trial:

Official Title: Evaluating the Hans Kai Program for Canadian Adults Via an 18-month Mixed Methods Randomized Controlled Trial

Included conditions:
- Mental Health
- Social Isolation
- Loneliness
- Health-Related Behavior

Study Armgroups:
- {'label': 'Hans Kai program', 'type': 'EXPERIMENTAL', 'description': 'The Hans Kai program is a peer-led, preventative, self-sustaining, community-based health promotion program for adults of all ages, genders, and socioeconomic circumstances who wish to maintain or improve their health. Hans Kai empowers individuals to take control of their own health and provides a unique opportunity for participants to have an active role in improving or maintaining their health and wellbeing.', 'interventionNames': ['Behavioral: Hans Kai Program']}
- {'label': 'Wait list control', 'type': 'NO_INTERVENTION', 'description': "Participants in the waitlist control group will remain as close to a 'typical' community member as possible as they will be able to receive any health programming normally available to them in Winnipeg, except the Hans Kai program. Standard of care is made available to all members of the control group as related to the healthcare rights of Canadians and Manitobans holding a Manitoba health card. NorWest staff will provide support to the community members without a Manitoba health card in obtaining one. The only deviation from standard care in the waitlist control group will be the pre- and post-intervention visits during which the control participants will fill out self-report questionnaires and undergo physical assessments."}

Interventions:
- {'type': 'BEHAVIORAL', 'name': 'Hans Kai Program', 'description': 'In Hans Kai, first, participants attend a 2-month Health School to develop the skills necessary to improve their health and wellbeing. The Health School includes sessions on health indicators; nutrition, grocery shopping and meal planning; physical activity; stress, coping, and health (sleep); and primary care through the years. After participants complete the Health School, they form Hans Kai groups (of 3 or more adults) and begin to meet regularly (at least once a month) independently of facilitators, in a self-sustaining model.', 'armGroupLabels': ['Hans Kai program']}

Primary Outcomes:
- {'measure': 'Mental Health', 'description': 'Mental health will be measured using the Mental Health Continuum Short Form (MHC-SF). The MHC-SF is a standardized self-report questionnaire that measures emotional, social, and psychological well-being by assessing the regularity with which respondents experience symptoms of positive mental health. The questionnaire includes 14 items asking respondents to indicate on a 6-point Likert scale (ranging from 0 = never to 5 = everyday) how often in the previous month they experienced symptoms of emotional, social, and psychological wellbeing. Item responses are summed, yielding a total score ranging from 0 to 70, with higher scores indicating more positive wellbeing.', 'timeFrame': '6 months'}

Please estimate the sample size based on the assumption: 
The assumptions include a standard deviation of 5 for normally distributed changes in MHC-SF scores, a significance level that provides 80% power, and a 15% dropout rate.
Sample size
          The primary analysis will be performed based on the pre- to post-intervention changes in the primary outcome, the Mental Health Continuum Short Form (MHC-SF) [23], comparing the mean change scores between the intervention and control participants, with a nested design to account for participant group membership in Hans Kai [24]. Based on data from previous studies [4, 24] and the RCT study design, we expect the changes from baseline MHC-SF scores within each subject group to be approximately normally distributed with a standard deviation of 5. The average within-group pre-post changes in MHC-SF scores in the Hans Kai prospective cohort study wereâ+â6.5 in 34 participants at 6Â months [18]. With a planned sample size that accounts for dropouts of 90 adults, with 60 intervention participants and 30 control participants, we would have a power of 80% to detect a true difference in the mean response of intervention and control participants ofâââ3.1 or 3.1 at the end of the 6-month RCT component [25]. This scenario assumes that the outcomes of each participant will be independent of the Hans Kai peer group they join. However, since part of the Hans Kai program includes forming groups, a very conservative power calculation considers the âeffectiveâ sample size for the Hans Kai program to be equal to the number of groups rather than the number of participants. We anticipate that 60 intervention participants will form 10 independent groups of six participants per group. In this very conservative scenario, with 10 groups in the intervention arm and 30 control participants, we would be able to detect a true difference in the mean scores of intervention and control participants ofâââ5.2 or 5.2 with 80% power. We believe that the actual study power will fall somewhere between the two scenarios presented here. With a starting sample size of 105 adults and an estimated 15% dropout rate during the study period [18], we expect to generate a minimum sample of approximately 90 participants at the 18-month follow-up.