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.
To estimate the price necessary to reach a given gross profit margin, you must first calculate the amount of revenue necessary to reach that margin. Begin by subtracting the gross profit margin from one. For instance, if the desired gross profit margin is 60 percent (0.6), the result of this first operation is 0.4.