Researchers were interested in nding out how the respiratory parameters in a group of individuals who were diagnosed with asthma responded to a six-week aerobic training intervention. Forced expired ratio (FER, %) is the product of the forced expired ratio in 1 second (FEVl, litres) divided by the forced vital capacity (FVC, litres) and was the parameter the researchers were most interested in. The bar chart representing the mean of the pre- and post-test data and the 95% confidence intervals for the mean are presented below. What does the 95% condence interval (CI) in the plot refer to