Frequency (statistics)
Frequency (statistics)
Types
The relative frequency (or empirical probability) of an event is the absolute frequency normalized by the total number of events:
Depictions
The following are some commonly used methods of depicting frequency:[2]
Histograms
A histogram is a representation of tabulated frequencies, shown as adjacent rectangles or squares (in some situations), erected over discrete intervals (bins), with an area proportional to the frequency of the observations in the interval. The height of a rectangle is also equal to the frequency density of the interval, i.e., the frequency divided by the width of the interval. The total area of the histogram is equal to the number of data. A histogram may also be normalized displaying relative frequencies. It then shows the proportion of cases that fall into each of several categories, with the total area equaling 1. The categories are usually specified as consecutive, non-overlapping intervals of a variable. The categories (intervals) must be adjacent, and often are chosen to be of the same size.[3] The rectangles of a histogram are drawn so that they touch each other to indicate that the original variable is continuous.[4]
Bar graphs
A bar chart or bar graph is a chart with rectangular bars with lengths proportional to the values that they represent. The bars can be plotted vertically or horizontally. A vertical bar chart is sometimes called a column bar chart.
Frequency distribution table
A frequency distribution table is an arrangement of the values that one or more variables take in a sample. Each entry in the table contains the frequency or count of the occurrences of values within a particular group or interval, and in this way, the table summarizes the distribution of values in the sample. An example is shown below
Rank | Degree of agreement | Number |
---|---|---|
1 | Strongly agree | 20 |
2 | Agree somewhat | 30 |
3 | Not sure | 20 |
4 | Disagree somewhat | 15 |
5 | Strongly disagree | 15 |
Interpretation
- 3....we may broadly distinguish two main attitudes. One takes probability as 'a degree of rational belief', or some similar idea...the second defines probability in terms of frequencies of occurrence of events, or by relative proportions in 'populations' or 'collectives'; (p. 101)...
- It might be thought that the differences between the frequentists and the non-frequentists (if I may call them such) are largely due to the differences of the domains which they purport to cover. (p. 104)
See also
Aperiodic frequency
Cumulative frequency analysis
Law of large numbers
Multiset multiplicity as frequency analog
Statistical regularity
Word frequency