Average score comparison(fictional) revealed the people put higher score for Coke as follows: (82.0 vs 77.8)
Based on the result, you may conclude that Coke is better than Pepsi. But is it really true????
Your co-worker may argue that you can split the result of the “same data” by sex a follows:
The result of male shows “Pepsi” get higher score than coke, which is also the case for female.
This is totally against the previous result while the results come from the same original data.
How would you explain such simple magic?