refers to the summary of important aspects of a data set. this includes collecting data, organizing the data , and then presenting the data in the forms of charts or tables
refers to drawing conclusions about a large set of data called a population based on a smaller set of sample data. a population is defined as all members of a specified group (not necessarily ppl) whereas a sample is a subset of that particular population
types of data ( 2 types)
Cross sectional data- refers to data collected by recording a characteristic of many subjects at the same point in time, or without regard to differences in time.
Time series data- refers to data collected by recording a characteristic of a subject over several time periods. Time series can include daily, monthly, quarterly, or annual observations.
consists of all items of interest in a statical problem
is a subset of the population.
example, the population of letters
in the alphabet would be the collection of all 26 letters. Randomly selecting a subset of letters would
create a sample
the certain aspect of a population (such as the average age or the percentage who said yes to a question), that measurement is called
If any aspect of a sample is described by a measure, it is called