A team of researchers wanted to find out what time of year would be best to administer a selection test for civil servants. The researchers wanted to discover when the candidates would perform at their best. So in a pilot study they ran four groups of 50 candidates. Each group sat on the same test on one of the following dates: 1st October (Autumn), 19th December (Winter), 3rd May (Spring) or 15th August (Summer). The test yields a score that can be assumed to be normally distributed.