Always ask yourself what the graph isn't showing. Sometimes distortions are the result of leaving out information. Distortions can also be created by adjusting one axis of the graph to make any change look more dramatic. Consider the hypothetical graphs below of per capita income in Elbonia over the last 100 years. Statistically significant difference vs. a difference that matters.
Statistics is a branch of mathematics that scientists use to analyze data from their experiments.
Statistics help them determine whether differences among different experimental groups can be attributed to differences in experimental conditions, or whether any differences are due simply to chance. It is important to realize that a statistically important difference among experimental groups does not mean that the difference is important. Thus, we say that even though the differences are statistically significant, they are not ecologically significant. Consider this another way. After doing some statistical calculations, we determine this difference is statistically significant.