1. The bowl of rice problem Suppose we take a random sample of rice from a bowl (blind folded):

2. Now we like to know what determines the amount of callories: Equation would be something like: Rice callory = a + b1 * size + e1 or if you like to test whether rice from Bandung and Java differs from Serang use Rice callory = a + b1 * size rice + b2 * Java + b3 * Bandung + e1

3. The bowl of rice problem Suppose we take a random sample of rice from many bowls (blind folded):

4. Equation still would be something like: Rice callory = a + b1 * size rice + e1 or if you like to test whether rice from Bandung and Java differs from Serang use: Rice callory = a + b1 * size rice + b2 * Java + b3 * bandung + bx * districtx + e1 BUT if this is the case:

6. Equation could be something like: Rice callory = a + b1 * size rice + b2 * Java + b3 * bandung + bx * districtx + e1 But then you’ve forgotten that the districts come from random sampling out of a large population of bowls of rice! If you intend to say something about ALL bowls of rice in a population use MULTILEVEL ANALYSIS.