Can we conclude that the old ratings have a direct causal effect on the new ratings? Explain briefly.

For Exercises 1–3, refer to the combined city–highway fuel economy ratings (mi/gal) for different cars. The old ratings are based on tests used before 2008 and the new ratings are based on tests that went into effect in 2008.

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Old 16 27 17 33 28 24 18 22 20 29 21 New 15 24 15 29 25 22 16 20 18 26 19