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.
The first of the most common direct marketing measurements is the cost per acquisition. The cost per acquisition can be determined by taking the total cost of the mailing and dividing it by the number of responses. For example, let s say the total cost of a mailing is $2,000 and 20 people respond.