It is a way of showing unorganized data notably to show results of an election, income of people for a certain region, sales of a product within a certain period, student loan amounts of graduates, etc.
It then shows the proportion of cases that fall into each of several categories, with the total area equaling 1.
[4] The rectangles of a histogram are drawn so that they touch each other to indicate that the original variable is continuous.
A frequency distribution table is an arrangement of the values that one or more variables take in a sample.
For example, the heights of the students in a class could be organized into the following frequency table.
Bivariate joint frequency distributions are often presented as (two-way) contingency tables: The total row and total column report the marginal frequencies or marginal distribution, while the body of the table reports the joint frequencies.
[6] Under the frequency interpretation of probability, it is assumed that as the length of a series of trials increases without bound, the fraction of experiments in which a given event occurs will approach a fixed value, known as the limiting relative frequency.
In fact, the term 'frequentist' was first used by M. G. Kendall in 1949, to contrast with Bayesians, whom he called "non-frequentists".
There are simple algorithms to calculate median, mean, standard deviation etc.
Statistical hypothesis testing is founded on the assessment of differences and similarities between frequency distributions.
A frequency distribution is said to be skewed when its mean and median are significantly different, or more generally when it is asymmetric.
The kurtosis of a frequency distribution is a measure of the proportion of extreme values (outliers), which appear at either end of the histogram.