Use ranges and totals together to distinguish a proof from a possible example.
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First lesson in this subject: Read data before calculating
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Every whole number in a recorded range is possible, including both endpoints. Supported means a claim holds in every dataset consistent with the records. Contradicted means it holds in none. Cannot determine means one permitted dataset makes it true and another makes it false. A tie makes “more than” false. When comparing rates, divide successes by attempts.
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First lesson in this subject: Read data before calculating
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Practice · Decide whether a claim follows from incomplete records, conflicts with them, or needs more information.
Book · Read distributions, question samples, and explore how groups and outliers change a conclusion.
Previous lesson · Distinguish a real effect from the change expected after selecting unusual first results.
Next lesson · Preserve labels and units, then use each group’s own total when converting counts to percentages.
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