Your friend David works for an online magazine and calls you late one night. He says “Dude(tte), can you help me out? I’m putting together an article and the submission deadline is in an hour. I want to quote an opinion poll result my publisher gave me, but they didn’t give me the margin of error, you know that plus-minus thingy they always give with the main opinion poll result. You’re taking that Stat class right? Here’s the info I have; the magazine asked 185 people if they had ever watched an episode of the original “Star Trek” TV series. According to the magazine 46% said yes. Can you help? Hey, are you still awake?”
What would be an acceptable margin of error for this survey result? Write a sentence below that David could use in his article that summarizes the results.
To determine an acceptable margin of error for this survey result, David needs to know the desired level of confidence. The level of confidence is the probability that the true proportion lies within the estimated margin of error. Common levels of confidence are 90%, 95%, and 99%. Without the level of confidence specified, we cannot determine the exact margin of error.
However, a commonly used level of confidence is 95%. If we assume a 95% level of confidence, David can use the following sentence in his article to summarize the results:
"According to a survey conducted by our magazine, 46% of the 185 respondents reported having watched an episode of the original "Star Trek" TV series, with a margin of error of (insert margin of error here) at a 95% confidence level."
To provide an accurate margin of error, David would need to calculate it using statistical formulas or consult with a statistician familiar with the specific survey methodology used.