Statistics Do Scatter Plots Represent Quantitative Or Categorical Variables

Very briefly, and simply put: if you plot the coinciding data points for X and Y, you can draw a line that runs through the mathematical “center” of that scatter of points. The correlation coefficient is a measure of that line, its slope.Like this:That is why scatter plots are used in correlation research.

You use scatter plots in any situation where you are examining two variables at the same time … and you want to show how much they correlate.The variables should be numerical, and in a scale that is not binary or categorical in any way. The scales must be continuous scales, like money, time, temperature, age, and so on.I’ve seen a scatter plot where the correlation was between length of eruptions of the geyser Old Faithful and how long between eruptions. Two numerical variables, using the same scale (minutes).An example of a categorical choice (which is bad) is when you compare sales correlated to product color. Product color is usually a set of categories that have no gradation between them in the data. Therefore the correlation is uninformative. Binary is just like the categorical, people answering yes/no and such.For categorical choices you pick a different graph, like a bar graph/bar chart. Or I suppose a pie chart if you’re trying to show the relationship between elements as a percentage of a whole.

Very briefly, and simply put: if you plot the coinciding data points for X and Y, you can draw a line that runs through the mathematical “center” of that scatter of points. The correlation coefficient is a measure of that line, its slope.Like this:That is why scatter plots are used in correlation research.

To answer this question, besides establishing the obvious that its used to visualize data, i believe it should also be elaborated in what information it provides through the visualization. The reason for this is that there are many visualization “tools” to communicate data and its important to understand why one visualization “tool” is chosen to express data compared to another visualization tool. Take for example Scatter plots vs Line graphs. Scatter plots are similar to line graphs in that they use horizontal and vertical axes to plot data points. However, they have a very specific purpose. Scatter plots show how much one variable is affected by another. The relationship between two variables is called their correlation . Variables can have either negative or positive correlation. For example if you measure if you were checking a grocery store’s inventory restock frequency, there will be a perfect positive correlation between the number of customers daily and the restock frequency, meaning the more customers there are then there will have an increased restock frequency. However note that if you were measuring restock frequency vs customer spend you will not get a perfect correlation because a customer can spend more money for less items. This is just one example of how and why a Scatter Plot is used compared to a line graph. Wrt a line graph it's similar to the scatter plot in that it also compares two variables but but one of these variables must be time. So its to monitor the change in the value of a variable over time or how time affects a variable. Scatter plots are not restricted to time as a variable unlike a line graph.

You use scatter plots in any situation where you are examining two variables at the same time … and you want to show how much they correlate.The variables should be numerical, and in a scale that is not binary or categorical in any way. The scales must be continuous scales, like money, time, temperature, age, and so on.I’ve seen a scatter plot where the correlation was between length of eruptions of the geyser Old Faithful and how long between eruptions. Two numerical variables, using the same scale (minutes).An example of a categorical choice (which is bad) is when you compare sales correlated to product color. Product color is usually a set of categories that have no gradation between them in the data. Therefore the correlation is uninformative. Binary is just like the categorical, people answering yes/no and such.For categorical choices you pick a different graph, like a bar graph/bar chart. Or I suppose a pie chart if you’re trying to show the relationship between elements as a percentage of a whole.

Scatter chart is a graph of plotted points that show the relationship between two sets of data. Scatter charts are used to investigate the possible relationship between two variables that both relate to the same "event". Scatter charts are similar to line charts in that they use horizontal and vertical axes to plot data points. However, scatter charts have a very specific purpose. Scatter charts show how much one variable is affected by another.There is a maxim in statistics that says, "correlation does not imply causality." In other words, your scatter plot may show that a relationship exists, but it does not and cannot prove that one variable is causing the other. There could be a third factor involved which is causing both, some other systemic cause, or the apparent relationship could just be a fluke. Nevertheless, the scatter plot can give you a clue that two things might be related, and if so, how they move together.When to Use Line vs. Scatter ChartsLine charts provide an excellent way to map independent and dependent variables that are both quantitative. When both variables are quantitative, the line segment that connects two points on the graph expresses a slope, which can be interpreted visually relative to the slope of other lines or expressed as a precise mathematical formula.Scatter plots are similar to line graphs in that they start with mapping quantitative data points. The difference is that with a scatter plot, the decision is made that the individual points should not be connected directly together with a line but, instead express a trend. This trend can be seen directly through the distribution of points or with the addition of a regression line. A statistical tool used to mathematically express a trend in the data.Scatter Charts ExamplesWorld Population and World Literacy Rate Scatter ChartA scatter chart is a type of plot or mathematical chart used to display values for typically two variables for a series of data. This world population and world literacy rate template here shows a positive coorelation between the two factors over a certain period of time.World Population and Carbon Dioxide Emissions Scatter ChartThe scatter chart examples above are created by Edraw scatter chart software. If you find them useful, you can free download the vector files and customize them with the software.