For each question, enter a lower and upper bound that you feel 95% confident contains the true answer.
This short quiz tests how well you understand a 95% confidence interval. For each question, you'll enter a lower and upper bound that you believe has a 95% chance of containing the true (actual) answer.
The 95% confidence interval (CI) is the standard statistical tool for expressing uncertainty in scientific research. The 95% CI reflects the range within which the true value would fall in about 95 out of 100 repeated samples. Because humans are consistently overconfident, people tend to choose intervals that are far too narrow—a finding replicated across many areas of research. This quiz helps us calibrate just how wide a truly 95% interval must be and gives us a clearer sense of what genuine statistical confidence looks like in practice. In short, when a study reports a 95% CI, it means we can be pretty darn confident that the true value lies within that interval...
When Pfizer released the first large randomized trial results for the COVID-19 vaccine, they reported that the vaccine was 95% effective, a number based directly on a 95% confidence interval calculated from 170 confirmed cases in a 43,000-person trial. Source: CNBC — “Pfizer says final data analysis shows Covid vaccine is 95% effective” https://www.cnbc.com/2020/11/18/coronavirus-pfizer-vaccine-is-95percent-effective-plans-to-submit-to-fda-in-days.html
Takes less than 10 minutes.