# What a histogram is?

1. Sep 29, 2009

### 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.