What is a Histogram? - Answers & Explanations

[Aeneas]

Can you please tell me what a histogram is? Some definitions seem to allow any bar chart where the areas of the bars are proportional to the frquency, which would allow underlying discrete distributions, such as he number of people expressing preferences for different makes of car, where the bars may be separated.

Other definitions seem to insist on an underlying continuous distribution where the bars are joined together, but in some areas there seems to be a convention that where the data are discrete but ordinal, the bars can be joined together. For example, the no. of wins in 400 m races achieved in the different lanes of a running track. Would this then be a histogram?

Very often you will see he bars joined together where he underlying variable is discrete but consists of consecutive numbers, such as when plotting the number of times a die comes up with the 1 to 6. Would that be a histogram?

Or is a histogram defined by having frequency density rather than frequency on the vertical axis?

If someone can sort the meaning of this term out for me I would be grateful. Or if this question has been asked many times before, could you give me a link to an answer?

Many thanks for any replies.

 

[Valkarie]

A histogram is a type of bar chart that displays the distribution of a numerical variable. It is used to represent the frequency of values within a set of data by displaying rectangles with heights (or areas) proportional to the frequency of occurrence of the values they represent. Histograms can be used with both continuous and discrete data and are often used in conjunction with other types of plots such as line graphs or scatter plots to provide a better visual representation of the data. The bars in a histogram can be joined together or separated depending on the type of data being represented. For example, when plotting the number of wins in 400m races achieved in different lanes of a running track, the bars can be joined together as the underlying variable is discrete but consists of consecutive numbers. Similarly, when plotting the number of people expressing preferences for different makes of car, the bars may be separated as the data is discrete. In either case, the vertical axis of the histogram typically displays either the frequency or the frequency density of the values.