Raw data provide little, if any, information to the decision makers. Thus, they need a means of converting the raw data into useful information. In this section, we discuss some of the frequently used methods of presenting and organizing data.[1]
The frequency (f) of a particular observation is the number of times the observation occurs in the data. The distribution of a variable is the pattern of frequencies of the observation. Frequency distributions are portrayed as frequency tables, histograms, or polygons.[2]
Frequency distribution is a summary of data presented in the form of class intervals and frequencies. Techniques for constructing a frequency distribution:
- determine the range of the raw data
- determine how many classes it will contain
- determine the width of the class interval
A frequency distribution shows the number of observations falling into each of several ranges of values. Frequency distributions are portrayed as frequency tables, histograms, or polygons.
Frequency distributions can show either the actual number of observations falling in each range or the percentage of observations. In the latter instance, the distribution is called a relative frequency distribution.[3]
A relative frequency distribution is just like a frequency distribution except that it consists of the proportions of occurrences instead of the numbers of occurrences for each value (or range of values) of a variable.
Did You Know?
Frequency is the number of observations of a given type.
Frequency distribution is a useful tool for grouping data.
A frequency distribution converts raw data into a meaningful pattern for statistical analysis.
Relative frequency is the # of observations of a given type divided by the total # of observations.
