Here is the design of a clinical trial:

Official Title: Randomized Fall Prevention Trial For Aging Females by Providing Supervised Exercises and Free Use of Municipal Recreation Facilities.

Included conditions:
- Accidental Falls
- Health Behavior
- Aging

Study Armgroups:
- {'label': 'Exercise intervention group', 'type': 'EXPERIMENTAL', 'description': 'Supervised exercise intervention of 12 months. One Taiji and one gym training per week for first six months followed by 6 months free independent use of municipal facilities, including gym, swimming hall and weight room. Written and oral health counselling provided.', 'interventionNames': ['Behavioral: Supervised physical exercise', 'Other: Health counselling']}
- {'label': 'Control group', 'type': 'ACTIVE_COMPARATOR', 'description': 'Control group, without any induced exercise intervention. Written and oral health counselling provided.', 'interventionNames': ['Other: Health counselling']}

Interventions:
- {'type': 'BEHAVIORAL', 'name': 'Supervised physical exercise', 'description': 'Supervised physical exercises in Taiji and weight training. Free use and access into municipal recreation and training facilities for one year.', 'armGroupLabels': ['Exercise intervention group']}
- {'type': 'OTHER', 'name': 'Health counselling', 'description': 'Health counselling, fall prevention strategies at home, information concerning municipal recreational services available.', 'armGroupLabels': ['Control group', 'Exercise intervention group']}

Primary Outcomes:
- {'measure': 'Risk of falls', 'description': 'Method of assessment; Personal fall diary. In case of fall, subject records the event into logbook. Outcome: Number of Falls during follow up.', 'timeFrame': 'Two years'}
- {'measure': 'Risk of fall', 'description': 'Biweekly text message (SMS) question concerning recent falls during last 2 weeks (Reply:Yes/No). In a case of a positive reply, following phone call to the subject to validate the event. Outcome: Number of Falls during follow up.', 'timeFrame': 'Two years'}

Please estimate the sample size based on the assumption: 
5% error margin, 80% power, 3% annual mortality, 20% drop-out rate for intervention group, 16% drop-out rate for control group, 80% compliance
Study power and sample size
        
          Fall rate and OSTPRE study data
          A primary outcome is falling. The entire OSTPRE-study cohort has been questioned for fall history in the preceding 12 months at 5-year intervals, most recently in 2014. At the 20-year questionnaire (in 2009), 35.0% of the OSTPRE women reported a fall during the last 12 months. Of these, 54.2% had fallen at least twice or more. Recent meta-analysis has reported very heterogeneous drop-out rates depending on factors such as geographic location, demography, duration and intensity of the protocol.14 Original estimation of the drop-outs, based on this meta-analysis, was set to 20% for the intervention group and 16% for the control group.
        
        
          Death rates
          Annual mortality in Finland from 2011 to 2012 was 2.5% for women aged 75â79 years.4 Respondents of the OSTPRE cohort have had lower mortality than the national average. Therefore, the cumulative mortality was estimated to have been 10% for the last 5 years (n=2502â2250).
        
        
          Summary of group sizes and study power
          The estimation was, with a 5% error margin, that 341 women in both groups would be required to give 80% power for detecting 31% fall reduction within a 30% general fall incidence during the 12-month follow-up. With a 3% annual mortality and 20% to 16% drop-out percentages for intervention and control samples, respectively, the estimated group sizes would be (341/0.77)+(341/0.81)=442+420. Adjusted for 80% compliance with mixed effects, the total group size was estimated to be 1078. However, the total final study population of 914 women (457 for each study group) presents an adequate sample size due to the significantly lower than estimated drop-out rate and a higher number of falls.