Observations recorded during research constitute data. There are three types of data i.e. nominal, ordinal, and interval data. Statistical methods for analysis mainly depend on type of data. Generally, data show picture of the variability and central tendency. Therefore, it is very important to understand the types of data.
1) Nominal data: This is synonymous with categorical data where data is simply assigned “names” or categories based on the presence or absence of certain attributes/characteristics without any ranking between the categories.[2] For example, patients are categorized by gender as males or females; by religion as Hindu, Muslim, or Christian. It also includes binominal data, which refers to two possible outcomes. For example, outcome of cancer may be death or survival, drug therapy with drug ‘X’ will show improvement or no improvement at all.