Reading Cumulative Frequency Graphs
Reading cumulative frequency graphs is like being a data detective – you're hunting for specific values that tell a story about your dataset. The median is always found at the halfway point of your total frequency.
To find the median, you'll need to locate 50% of your total data points on the y-axis, then read across to your curve and down to find the corresponding value. In this challenge completion example, with the median at 68 seconds, half the people finished faster and half took longer.
Finding how many people exceed a certain value is equally straightforward. You simply read the cumulative frequency at your target value (80 seconds here) and subtract this from the total to get your answer.
Quick Tip: Always remember that cumulative frequency shows "up to and including" that value, so think carefully about whether you want "more than" or "at least" when interpreting your results.
