1 Onset of sleep from time the lights were turned off; this is called  sleep onset latency  and normally is less than 20 minutes. ( 2 Note that determining sleep and awake is based solely on the EEG. Patients sometimes feel they were awake when the EEG shows they were sleeping.
The direct cost margin is calculated by taking the difference between the revenue generated by the sale of goods or services and the sum of all direct costs associated with the production of those goods, divided by the total revenue.
EBITDA margin. One way to get a more realistic profit picture is to calculate EBITDA margin. To determine EBITDA margin, a business must first calculate its EBITDA and then divide that number by total revenue. EBITDA Margin = EBITDA Ã· Total Revenue. This result helps show how much operating expenses are eating into a company's profits. In the end, the higher the EBITDA margin, the less risky a company is considered financially.