Mrs Smith conducts an experiment to investigate whether eating a bar of chocolate during break time improves her students’ problem-solving skills.

She divides her class into two groups; students with the last name starting with A to L in the first group and M to Z in the second group. The first group is given chocolate bars during break time, whereas the second group is given muesli bars.

After three weeks, Mrs Smith gives her students a problem-solving skills test and finds, on average, the students who ate muesli bars scored 6 marks better than the students who ate chocolate.

Mrs Smith: “So we can conclude then, eating muesli bars during break time improves children’s problem-solving skills!”