A researcher hypothesised that low blood glucose level impair mathematical reasoning ability. To investigate this, participants were administered a difficult mathematical test at three time points relative to their last meal: immediately following a meal (AFTER), midway between two meals (BETWEEN), and immediately before a meal (BEFORE). Each participant completed all three time points. Order of tests was counterbalanced across participants to control for order effects. Additionally the researcher was interested in investigating whether any effect of blood glucose levels on mathematical ability could be offset by drinking high- glucose sports drinks. Each participant was randomly allocated to one of two groups before beginning the experiment: one group drank a cup of water before completing each math test, the other group drank a high glucose sports drink. Performance on each math test was recorded as the percentage of problems correctly solved in ten