Scatter plot
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Scatter plot | |
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Seven Basic Tools of Quality | |
First described by | John Herschel[1] |
Purpose | To identify the type of relationship (if any) between two quantitative variables |
A scatter plot, also called a scatterplot, scatter graph, scatter chart, scattergram, or scatter diagram,[3] is a type of plot or mathematical diagram using Cartesian coordinates to display values for typically two variables for a set of data. If the points are coded (color/shape/size), one additional variable can be displayed. The data are displayed as a collection of points, each having the value of one variable determining the position on the horizontal axis and the value of the other variable determining the position on the
Overview
A scatter plot can be used either when one continuous variable is under the control of the experimenter and the other depends on it or when both continuous variables are independent. If a
A scatter plot can suggest various kinds of correlations between variables with a certain confidence interval. For example, weight and height would be on the y-axis, and height would be on the x-axis. Correlations may be positive (rising), negative (falling), or null (uncorrelated). If the dots' pattern slopes from lower left to upper right, it indicates a positive correlation between the variables being studied. If the pattern of dots slopes from upper left to lower right, it indicates a negative correlation. A line of best fit (alternatively called 'trendline') can be drawn to study the relationship between the variables. An equation for the correlation between the variables can be determined by established best-fit procedures. For a linear correlation, the best-fit procedure is known as linear regression and is guaranteed to generate a correct solution in a finite time. No universal best-fit procedure is guaranteed to generate a correct solution for arbitrary relationships. A scatter plot is also very useful when we wish to see how two comparable data sets agree to show nonlinear relationships between variables. The ability to do this can be enhanced by adding a smooth line such as LOESS.[5] Furthermore, if the data are represented by a mixture model of simple relationships, these relationships will be visually evident as superimposed patterns.[citation needed]
The scatter diagram is one of the
Scatter charts can be built in the form of bubble, marker, or/and line charts.[7]
Example
For example, to display a link between a person's lung capacity, and how long that person could hold their breath, a researcher would choose a group of people to study, then measure each one's lung capacity (first variable) and how long that person could hold their breath (second variable). The researcher would then plot the data in a scatter plot, assigning "lung capacity" to the horizontal axis, and "time holding breath" to the vertical axis.[citation needed]
A person with a lung capacity of 400
Scatter plot matrices
For a set of data variables (dimensions) X1, X2, ... , Xk, the scatter plot matrix shows all the pairwise scatter plots of the variables on a single view with multiple scatterplots in a matrix format. For k variables, the scatterplot matrix will contain k rows and k columns. A plot located on the intersection of row and jth column is a plot of variables Xi versus Xj.[8] This means that each row and column is one dimension, and each cell plots a scatter plot of two dimensions.[citation needed]
A generalized scatter plot matrix[9] offers a range of displays of paired combinations of categorical and quantitative variables. A mosaic plot, fluctuation diagram, or faceted bar chart may be used to display two categorical variables. Other plots are used for one categorical and one quantitative variables.
See also
- Data and information visualization
- Rug plot
- Bar graph
- Line chart
- Scagnostics
- Dot plot (statistics)
- Parity plot
References
- PMID 15812820.
- ^ Visualizations that have been created with VisIt at wci.llnl.gov. Last updated: November 8, 2007.
- ISBN 978-0-697-21595-6.
When we search for a relationship between two quantitative variables, a standard graph of the available data pairs (X,Y), called a scatter diagram, frequently helps...
- ISBN 0-534-39402-7
- ISBN 978-0963488404.
- Milwaukee, Wisconsin: American Society for Quality. p. 15. Retrieved 2010-02-05.
- ^ "Scatter Chart – AnyChart JavaScript Chart Documentation". AnyChart. Archived from the original on 1 February 2016. Retrieved 3 February 2016.
- ^ Scatter Plot Matrix at itl.nist.gov.
- S2CID 28344569.
External links
- Media related to Scatterplots at Wikimedia Commons
- What is a scatterplot? Archived 2020-08-07 at the Wayback Machine
- Correlation scatter-plot matrix for ordered-categorical data – Explanation and R code
- Density scatterplot for large datasets (hundreds of millions of points)