Professor Johnston Has Found a Strong Positive Correlation Between Wearing

question 41

Multiple Choice

Professor Johnston has found a strong positive correlation between wearing neckties and the frequency of strokes (r = 0.89) .He thinks that the necktie reduces blood flow to the brain,preventing the brain from receiving enough oxygen.Professor Johnston and his associates claim to have proven that wearing neckties causes strokes.What error has Professor Johnston made?

• A)An r = 0.89 is not a very large r-value.
• B)Professor Johnston is drawing a causal conclusion from correlational findings.
• C)Not everyone who wears a necktie wears it very tight.
• D)Professor Johnston should know that there are other ways for blood to reach the brain.

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Definitions:

Proportions

Statements that two ratios are equal, showing the equivalence between two sets of numbers or measurements.

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Unknown Quantities are values in mathematical equations or problems that have not been determined or identified yet.

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