Tham khảo tài liệu 'engineering statistics handbook episode 1 part 9', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | . Scatter Plot Outlier the outlying point . NIST SEMATECH HOME TOOLS AIDS Search BACK NỄXĨ http div898 handbook eda section3 2 of 2 5 1 2006 9 57 06 AM . Scatterplot Matrix ENGINEERING STATISTICS HANDBOOK hW tools raids lỉEÂtCH BACK Nixf 1. Exploratory Data Analysis . EDA Techniques . Graphical Techniques Alphabetic . Scatter Plot . Scatterplot Matrix Purpose Check Pairwise Relationships Between Variables Given a set of variables X1 X2 . Xk the scatterplot matrix contains all the pairwise scatter plots of the variables on a single page in a matrix format. That is if there are k variables the scatterplot matrix will have k rows and k columns and the ith row andyth column of this matrix is a plot of Xị versus Xj. Although the basic concept of the scatterplot matrix is simple there are numerous alternatives in the details of the plots. 1. The diagonal plot is simply a 45-degree line since we are plotting Xi versus Xị. Although this has some usefulness in terms of showing the univariate distribution of the variable other alternatives are common. Some users prefer to use the diagonal to print the variable label. Another alternative is to plot the univariate histogram on the diagonal. Alternatively we could simply leave the diagonal blank. 2. Since Xi versus Xj is equivalent to Xj versus Xi with the axes reversed some prefer to omit the plots below the diagonal. 3. It can be helpful to overlay some type of fitted curve on the scatter plot. Although a linear or quadratic fit can be used the most common alternative is to overlay a lowess curve. 4. Due to the potentially large number of plots it can be somewhat tricky to provide the axes labels in a way that is both informative and visually pleasing. One alternative that seems to work well is to provide axis labels on alternating rows and columns. That is row one will have tic marks and axis labels on the left vertical axis for the first plot only
