Similarity

• Lets have three existing cases:

  Name	Income	Expenses	Assets	Result
  Chris	25000	20000	50000	Yes
  Pat	25000	25000	50000	No
  Sandy	50000	45000	-25000	No

• Mel wants to take out a loan (everyone asks for 10000), and makes 35000 per year spend 25000 and has 10000 in assets. Should Mel get a loan.
• You need to compare to the others. How do you compare? Which is Mel closest to.
• Mel shares one feature exactly with Pat, so is that closest?
• Measuring similarity is really important.
• Here you might have a complex way of comparing, get total surplus multiply that by 5, and add to assests.
• So Mel is 60000, Chris is 75000, Pat 50000 and Sandy 0
• Which is Mel nearest to. Here you could say Pat(No), but you could also say Chris(Yes) or Maybe because it's between a No and Yes
• In this case we've taken all the features and combined them to get one value. You can't always do this and it's not always wise.