The idea
Chips and cold drinks
Supermarkets notice that people who buy chips often buy cold drinks too. So they place them near each other, or offer a combo.
Finding these patterns from shopping baskets is market-basket analysis, and the patterns are association rules:
{chips} → {cold drink} “if chips, then cold drink”
AntecedentThe “if” part (chips). ConsequentThe “then” part (cold drink).