What is the difference between Even Split, Sampling, and Random Sampling market test modes?

Environment:

Market testing
Oracle B2C Service, Outreach and Feedback

Resolution:

You can use market testing to fine tune your mailings for a more effective marketing strategy. By sending the mailing to smaller subsets of your audience, you can gauge the response and modify the message to make it more effective before sending it to the audience as a whole. You can change the market testing mode only before the mailing has been sent and the delivery status is either Draft or Suspended.

• Even Split: This mode sends your test messages to equal portions of your audience. For example, if you created four messages, each message would be sent to twenty-five percent of your audience. In this way, you can test different content and designs for use if future mailings. When you press 'Send' each message will automatically send to their portion of the audience.  The messages send individually with the next message starting automatically once the previous message has completed sending to its portion.
  
  
• Sampling: This mode sends test messages to a percentage of the audience you specify. After the test messages are sent, you send a final message to remaining audience members. For example, you could send tow messages to five percent of your audience each. After determining the most effective message, you would send a final message to any audience members who had not received a test message. 
  
  
• None: Use None to send a single message to all contacts who receive the transactional mailing.

When you change from Even Split or Sampling to None, a prompt asks you which message to keep.  Select the appropriate message. Other sampling messages are deleted. Mailing content and proof history for the discarded messages are also lost when switching from Even Split or Sampling to None.

To change the market testing mode: 

1. From the Mailings screen, click on the mailing you want to change.
2. On the messages tab of an open mailing, click the information bar (just above the From address field) and select Change Market Testing Mode. The Select Market Testing Mode window opens.
3. You can also access this window on the Summary tab by clicking Change next to Market Testing.
4. To send a test message to equal portions of your audience, select the Even Split radio button.
5. To send a test message to a percentage of your audience, select the Random Sampling radio button.
6. To deactivate market testing, select the None radio button.
7. Click the OK button.