Unit 6 · Identifying Sufficient Information

Jacob 3/14 vs Nicole 11/12 — What Did Tahnee Miss?

Lesson 10 of 12

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Jacob won 3 of 14 chess club games (21%); Nicole won 11 of 12 (92%). Tahnee says Nicole's higher fraction proves she's better. Which sentence shows Tahnee's mistake? The flaw is the same as comparing sports win rates without accounting for opponent difficulty — a higher win rate against easy opponents doesn't beat a lower win rate against hard ones.

Chapters

0:00Introduction
0:22The Question
1:14Step 1: Identify Tahnee's reasoning
1:37Step 2: The missing variable
2:06Step 3: Test each option
2:45Correct answer

Question

| The students in Tahnee's class must choose either Jacob or Nicole to represent their class in the school chess competition.

Jacob won 3 of his last 14 games in the chess club.

Nicole won 11 of her last 12 games in the chess club.

Tahnee: "Nicole has won a higher fraction of her recent games at the club, so she must be the better player. She should represent our class."

Which one of the following sentences shows that Tahnee has made a mistake?

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