DefinitionA population is a particular group of interest.A variable is a value or characteristic that changes among members of the population.Data are the counts, measurements, or observations gathered about a specific variable in a population in order to study it.A census is a study in which data are obtained from every member of the population.A parameter is a numerical description of a population characteristic.A sample is a subset of the population from which data are collected.Sample statistics are numerical descriptions of sample characteristics.The branch of descriptive statistics, as a science, gathers, sorts, summarizes, and displays the data.The branch of inferential statistics, as a science, involves using descriptive statistics to estimate population parameters.Qualitative data consist of labels or descriptions of traits.Quantitative data consist of counts or measurements.Continuous data are quantitative data that can take on any value in a given interval and are usually measurements.Discrete data are quantitative data that can take on only particular values and are usually counts.Data at the nominal level of measurement are qualitative data consisting of labels or names.Data at the ordinal level of measurement are qualitative data that can be arranged in a meaningful order, but calculations such as addition or division do not make sense.Data at the interval level of measurement are quantitative data that can be arranged in a meaningful order, and differences between data entries are meaningful.Data at the ratio level of measurement are quantitative data that can be ordered, differences between data entries are meaningful, and the zero point indicates the absence of something.An observational study observes data that already exist.An experiment generates data to help identify cause-and-effect