Indicate the type of statistical test to be used, with justification.

A researcher designed an experiment to assess the effects of prolonged inhalation of cadmium oxide. Fifteen laboratory animals served as experimental subjects, while 10 similar animals served as controls. The variable of interest was haemoglobin level following the experiment. The results are shown in the table below. Researchers wish to know that haemoglobin level differs significantly between unexposed and exposed animals to prolonged inhalation of cadmium oxide. Hemoglobin Determinations (grams) for Laboratory Animals Exposed Animals (X) Unexposed Animals ()) 14.4 17.4 14.2 16.2 13.8 17.1 16.5 17.5 14.1 15.0 16.6 16.0 15.9 16.9 15.6 15.0 14.1 16.3 15.3 16.8 15.7 16.7 13.7 15.3 14.0