Ans. is 'a' i.e. Quantitative data of a group of patients Statistical data are of two typesQualitativeQuantitativeQualitative data is one in which the size or magnitude of the characteristic or attribute cannot be measured.there is only one variable i.e. the number of persons and not the characteristic or attribute persons with the same charactersitic are counted to form specific groups or classes. eg: male/female, black/white, urban/suburban/rural, vaccinated/not vaccinated, treated/not treated.as seen in the example the attribute or characteristic, vaccinated/not vaccinated cannot be measured. Only the frequency of persons vaccinated or not vaccinated varies.Qualitative data are represented in Nominal or Ordinal scale.Quantitative data is one in which the characteristic or attribute is variable. It has a magnitude that can be measured. eg. : height, weight, temperature, blood pressure, pulse ratehere there are two variables, both the characteristic i.e. height or weight and frequency of persons. quantitative data are represented on Interval or Ratio scales.The statistical details presented, for easy viewing and understanding, in the form of tables, graphs and diagrams.Quantitative data can be presented through following graphs :Histogram Frequency polygon Frequency curve Line chart or graph Scatter or dot diagramQualitative data can be represented through following diagrams :Bar diagramPie or sector diagramPictogramMap diagram or spot map.