Learn how to use statistics to understand the significance of the latest political polling results and to keep yourself from being duped by misleading information.
How to Know if Political Poll Results are Significant Or Not
Now, let’s go back to our original question: Should you trust the results of a poll? Well, let’s return to our imaginary presidential poll in which candidate A received the support of 42% of the population and candidate B received the support of 46% of the population, with a margin of error of ±3%. This means that candidate A could have up to 45% of the support and candidate B could have as little as 43% of the support, so that while the poll seems to indicate a 46% to 42% lead for candidate B, it cannot actually be used to determine who is really leading—no matter how many times pundits claim otherwise—since the margin of error is too big.
If, however, the margin of error were smaller—something like ±1.5% instead of ±3% could be achieved by polling a significantly larger sample of the population—then candidate B’s 4% lead would actually be significant since (with 95% confidence) candidate B would have a minimum of 44.5% of the vote to the maximum 43.5% support of candidate A. The general rule of thumb is that the lead must be at least twice the margin of error to be significant, and the quick and dirty tip is therefore to be sure and pay attention to margins of error—without them, poll results are essentially meaningless.
That’s all the math we have time for today. And that’s all the time we’re going to take to talk about statistics too—for now, at least. In upcoming episodes, we’ll be heading back to math basic training to talk some more about math fundamentals.
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Until next time, this is Jason Marshall with The Math Dude’s Quick and Dirty Tips to Make Math Easier. Thanks for reading, math fans!
Poll image from Shutterstock