Here is the design of a clinical trial:

Official Title: Randomized Controlled Trial Examining Real-World Effectiveness of a Prescription Digital Therapeutic for the Treatment of Insomnia

Included conditions:
- Insomnia Chronic

Study Armgroups:
- {'label': 'PEAR-003b PDT Intervention', 'type': 'EXPERIMENTAL', 'description': 'Participants will receive the PEAR-003b digital therapeutic, a Fitbit, and materials on sleep hygiene and healthy sleep tips. Using the Hugo platform, patient-generated engagement data, healthcare utilization, and patient activity/clinical outcomes for patients with insomnia will also be collected.', 'interventionNames': ['Device: PEAR-003b PDT Intervention', 'Device: Fitbit', 'Behavioral: Sleep education materials']}
- {'label': 'Control Arm', 'type': 'PLACEBO_COMPARATOR', 'description': 'Participants will receive a Fitbit, and materials on sleep hygiene and healthy sleep tips. Using the Hugo platform, patient-generated engagement data, healthcare utilization, and patient activity/clinical outcomes for patients with insomnia will also be collected.', 'interventionNames': ['Device: Fitbit', 'Behavioral: Sleep education materials']}

Interventions:
- {'type': 'DEVICE', 'name': 'PEAR-003b PDT Intervention', 'description': 'The PEAR-003b digital therapeutic delivers CBT-I via mobile devices as 6 treatment core modules over 9 weeks.', 'armGroupLabels': ['PEAR-003b PDT Intervention']}
- {'type': 'DEVICE', 'name': 'Fitbit', 'description': 'Patients will receive a Fitbit and receive standard of care', 'armGroupLabels': ['Control Arm', 'PEAR-003b PDT Intervention']}
- {'type': 'BEHAVIORAL', 'name': 'Sleep education materials', 'description': 'Patients will receive sleep hygiene and healthy sleep tips.', 'armGroupLabels': ['Control Arm', 'PEAR-003b PDT Intervention']}

Primary Outcomes:
- {'measure': 'Change in Insomnia Severity', 'description': "Insomnia will be measured by the Insomnia Severity Index (ISI) score. Participants rate the severity of sleep problems (e.g. problems with sleep onset, sleep maintenance, and early morning awakening), interference with daytime functioning, how noticeable the impairment is to others, distress or concern caused by the sleep problem(s), as well as satisfaction with the current sleep pattern on a 5-point Likert scale. The ISI's total score ranges from 0 (not clinically significant) to 28 (clinically significant)", 'timeFrame': 'From baseline to 9 weeks post randomization'}

Please estimate the sample size based on the assumption: 
Alpha 0.05, 25% dropout rate, normally distributed outcomes, and the analysis may draw from outcome values recorded at baseline and each follow-up time.
Sample size calculation
        Our sample size was determined assuming 90% power to detect an effect size of d=0.52âfor the main outcome (change in ISI from baseline to 9-week postrandomisation),50 with alpha 0.05 using the PASS software (PASS 15) to detect a clinically meaningful change.53 This effect size is 1/2 to 1/3 of what we have seen previously. Because this effect size is smaller than the levels demonstrated in RCTs, we are adequately powered to detect changes of interest in the main ISI outcome. We further note that this calculation is conservative because the analysis may optionally draw from outcome values recorded at baseline and each follow-up time. Because the models assume that each outcome is normally distributed, the outcome effects represent the average amount each outcome is expected to change with the incremental shift in any explanatory variable. We will recruit a total of 100 participants and will randomly assign them to treatment and control arms based on a 50% probability of assignment. We also assume a 25% rate of dropout between baseline and the end of follow-up, resulting in an effective sample size of N=80. The dropout attrition rate is based on prior research on the SHUTi intervention where study dropout attrition at 1âyear has been as high as 50%50 although another study was as low as 4%21 at the end of treatment evaluation. This may be due to the fact that differential dropout is frequently greater in active than control conditions in clinical trials due to the added psychological effort required in the active group and/or to attainment of treatment goals.