I assume that the data you have are measures of anatomical distance between the "inferior anterior border of the maxilla to the inferior aspect of the nasal bone". The data set consists of 1100 data points (900+200). You talked of test of significance. Before one conducts a statistical test, there must be a hypothesis (or claim) you or someone is making about the distance you are measuring. For instance, the claim could be something like 'the mean distance of the inferior anterior border of the maxilla to the inferior aspect of the nasal bone is.....'
If there is such a claim, it is then possible to conduct a test to show whether the claim is true or false: in other words, test of significance. oparairoegbu