The article introduces a method to test if the average of a set of numbers has changed over time. By taking sequential samples, researchers found that they could save a lot of time and effort compared to taking all samples at once. The size of the new sample depends on how much the average has shifted and is not affected by the size of the original sample. Using this sequential method can save up to six times the effort needed for traditional sampling methods, especially when looking for small changes. Not using this method could increase the total sample size by 50-75%.