What is a line plot?

Define line plot:
A line plot is a method of data representation. Of the many methods to represent statistical data, one is graphical representation. A line plot is a type of graphical representation of data. When frequency of data is plotted along a number line it is called a line plot. A line plot makes sense only when the number of observations is lesser than 25. For small number of observations a line plot gives a very good visual representation of data. Following are some examples of line plots:

Line plot graph:

The first step for any data representation is collection of data. Data can be collected from various sources such as, the internet, person to person observations, questionnaire, survey records etc. After collecting the data we can proceed to make the line plot. For making a line plot, first we need to come to a suitable scale for plotting the data. As we can see in the two examples above, in one the scale 1 unit = 5 marks and each unit is subdivided to 5 marks. That is because, the marks are all lying between 30 to 50. For the second example we see that the scale is 1 unit = one day, since we are interested in number of cars sold each day.

Once we decide on the scale, we can actually make the line and mark the numbers as per our scale. Ensure that the distance between consecutive points on the line is proportional to the number the point represents.

Next take the data and list it. Now for each observation, mark a X over the number on the number line that is equal to the observation value. For example, if we have 4 cars sold on Monday, then we mark four Xs over the Monday mark of the number line. Similarly we go on for each of the observation from the data available with us.
See the example chart below;

Understanding the line plot:

We have seen above how to make a line plot. But now the question is that if such a plot is given to us, how do we read that plot (or understand the line plot)? A line plot easily brings out the outlier. An outlier is an observation that is very large or very small as compared to all of the other observations. A line plot also helps us identify gaps and clusters in observations.