qqplot | Command || Coef View | Graph Command | Group View | Matrix View | Rowvector View | Series View | Sym View | Vector View |

Display a quantile-quantile graph.

Plots the (empirical) quantiles of a series or matrix column against either the quantiles of a theoretical distribution or the empirical quantiles of other series or columns in the group or matrix. You may specify the theoretical distribution and/or the method used to compute the empirical quantiles as options.

Syntax

qqplot(options) o1 [o2 o3 ... ]

object_name.qqplot(options) analytical_spec(arg) [categorical_spec(arg)]

where o1, o2, ..., are series or group objects.

When used as a command, qqplot displays the theoretical qq-plot against a fitted normal distribution.

When used to display the view of an object, you must specify a theoretical or empirical quantile graph in the analytical_spec (see “Analytical Spec”).

Options

Multiple series pair options (categorical graph settings will override these options)

s | Plot in a single graph (applies only to theoretical QQ and symmetry Q-Q graphs). |

mult= mat_type | Multiple series or column handling: where mat_type may be: “pairs” or “p” - pairs, “mat” or “m” - scatterplot matrix, “lower” or “l” - lower triangular matrix. |

Template and printing options

o=template | Use appearance options from the specified template. template may be a predefined template keyword (“default” - current global defaults, “classic”, “modern”, “reverse”, “midnight”, “spartan”, “monochrome”) or a graph in the workfile. |

t=graph_name | Use appearance options and copy text and shading from the specified graph. |

b / -b | [Apply / Remove] bold modifiers of the base template style specified using the “o=” option above. |

w / -w | [Apply / Remove] wide modifiers of the base template style specified using the “o=” option above. |

reset | Resets all graph options to the global defaults. May be used to remove existing customization of the graph. |

p | Print the graph. |

The options which support the “–” may be preceded by a “+” or “–” indicating whether to turn on or off the option. The “+” is optional.

Panel options

The following option applies when graphing panel structured data.

panel=arg (default taken from global settings) | Panel data display: “stack” (stack the cross-sections), “individual” or “i” (separate graph for each cross-section). (Note: more general versions of these panel graphs may be constructed as categorical graphs.) |

Analytical Spec

Specify the type of quantile-quantile graph you wish to create in the analytical spec. For a description of quantile-quantile graphs, see “Analytical Graph Types”. The analytical spec should be in the form:

qq_type(type_options)

where qq_type may be one of the following keywords:

theory | Theoretical quantile-quantile plot. |

empirical | Empirical quantile-quantile plot (requires at least two series or columns of a matrix) |

symmetry | Quantile quantile symmetry plot. |

You may provide multiple theoretical qq-plot elements, but may not have more than one empirical qq-plot, nor may you mix the two.

Each type has its own set of options, to be entered in type_options:

Theoretical Options

dist=arg | arg can be: “normal”, “exp” - exponential, “logit” - logistic, “uniform” - uniform, “xman” - extreme max, “xmin” - extreme min, “chisq” - chi-squared, “pareto” - Pareto, “weibull” - Weibull, “gamma” - gamma, “tdist” - Student’s t-distribution. |

p1=int | Set first parameter. |

p2=int | Set second parameter. |

p3=int | Set third parameter. |

q = arg | Set the quantile method, where arg can be: “r” - Rankit-Cleveland, “o” - Ordinary, “v” - van der Waerden, “b” - Blom, “t” - Tukey, “g” - Gumbel. |

noline | Don’t display a fit line. |

m=int | Set the iterations maximum. (Applies to logistic, extreme max, extreme min, chi-squared, Weibull, gamma, or t-distributions.) |

c =int | Sets the convergence criterion. (Applies to logistic, extreme max, extreme min, chi-squared, Weibull, gamma, or t-distributions.) |

s | Use user-specified starting values, supplied in the C coefficient vector in the workfile (default uses EViews supplied starting values). (Applies to logistic, extreme max, extreme min, chi-squared, Weibull, gamma, or t-distributions.) |

leg=arg | Specify the legend display settings, where arg can be: “def” - default, “n” - none, “s” - short, “det”- detailed. |

Empirical Options

q=arg | Set the quantile method, where arg can be: “r” - Rankit-Cleveland, “o” - Ordinary, “v” - van der Waerden, “b” - Blom, “t” - Tukey, “g” - Gumbel. |

noline | Don’t display a regression line. |

leg=arg | Specify the legend display settings, where arg can be: “def” - default, “n” - none, “s” - short, “det”- detailed. |

Examples

Theoretical examples

qqplot(s) inf unemp

displays theoretical qq-plots for INF and UNEMP against fitted normal distributions in a single frame.

group g1 inf unemp

g1.qqplot theory

displays theoretical qqplots of INF and UNEMP compared with normal distributions fitted to the data in each series. The graphs include fit lines and are displayed in separate frames.

g1.qqplot(s) theory(dist=exp)

compares INF and UNEMP with fitted exponential distributions, and displays the graphs in a single frame.

g1.qqplot(s) theory(dist=exp, p1=5)

plots the series against the quantiles of an exponential distribution with parameter 5 in a single frame.

Empirical Examples

group g2 ser1 ser2 ser3 ser4

g2.qqplot empirical

displays empirical qqplots for pairs of series in G2. The default behavior is to plot the first series in the group (SER1) against the remaining series (SER2, SER3, and SER4). The graphs include fit lines and are displayed in separate graph frames.

g1.qqplot(mult=pair) empirical(noline)

displays qqplots of SER1 versus SER2 and SER3 versus SER4 in separate graph frames, without a regression line.

Categorical examples

g1.qqplot theory within(age)

displays theoretical qq-plots with the series in G1 treated as the within factor and @SERIES treated as the across factor. The qq-plots for each series in G1 will be displayed in separate frames, with multiple qq-plots for each AGE category shown in each frame.

g1.qqplot(mult=p) empirical across(age)

displays empirical qq-plots for categories of AGE in separate graph frames.

Cross-references

See “Graphing Data” for a detailed discussion of graphs in EViews, and “Templates” for a discussion of graph templates. See Graph::graphfor graph declaration and other graph types.