Exercise 4 - Significance

We did not find meaningful differences between the poll results from grade A- and grade C- polls in this subset of the data, which only contains polls for about a week before the election. Imagine we expanded our analysis to include all election polls and we repeat our analysis. In this hypothetical scenario, we get that the p-value for the difference in prediction success if 0.0015 and the odds ratio describing the effect size of the performance of grade A- over grade B- polls is 1.07.

Based on what we learned in the last section, which statement reflects the best interpretation of this result?

Possible Answers

The p-value is below 0.05, so there is a significant difference. Grade A- polls are significantly better at predicting winners.
The p-value is too close to 0.05 to call this a significant difference. We do not observe a difference in performance.
The p-value is below 0.05, but the odds ratio is very close to 1. There is not a scientifically significant difference in performance.
The p-value is below 0.05 and the odds ratio indicates that grade A- polls perform significantly better than grade C- polls.

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