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.
Step 1. Subtract the total costs of your goods from the revenues the sales generate to find your gross profit. For example, if you purchase $10,000 of goods and sell them for $11,800, you would subtract $10,000 from $11,800 to get a profit of $1,800.Step 2. Divide your gross profit by your total revenue generated.In this example, you would divide $1,800 by $11,800 to get 0.15. Related Reading: The Difference Between Gross Margin Dollars & Percentage of Revenue. Step 3. Multiply the result from Step 2 by 100 to find the gross profit margin percentage.Finishing the example, you would multiply 0.15 by 100 to find that your gross profit margin equals 15 percent.tep 3. Multiply the result from Step 2 by 100 to find the gross profit margin percentage. Finishing the example, you would multiply 0.15 by 100 to find that your gross profit margin equals 15 percent.