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| Cox, Nicholas J.. |
| Stem-and-leaf displays have been widely taught since John W. Tukey publicized them energetically in the 1970s. They remain useful for many distributions of small or modest size, especially for showing fine structure such as digit preference. Stata’s implementation stem produces typed text displays and has some inevitable limitations, especially for comparison of two or more displays. One can re-create stem-and-leaf displays with a few basic Stata commands as scatterplots of stem variable versus position on line with leaves shown as marker labels. Comparison of displays then becomes easy and natural using scatter, by(). Back-to-back presentation of paired displays is also possible. I discuss variants on standard stem-and-leaf displays in which each distinct... |
| Tipo: Article |
Palavras-chave: Stemplot; Stem-and-leaf; Graphics; Distributions; Digit preference; Research Methods/ Statistical Methods. |
| Ano: 2007 |
URL: http://purl.umn.edu/119285 |
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| Cox, Nicholas J.. |
| Density probability plots show two guesses at the density function of a continuous variable, given a data sample. The first guess is the density function of a specified distribution (e.g., normal, exponential, gamma, etc.) with appropriate parameter values plugged in. The second guess is the same density function evaluated at quantiles corresponding to plotting positions associated with the sample’s order statistics. If the specified distribution fits well, the two guesses will be close. Such plots, suggested by Jones and Daly in 1995, are explained and discussed with examples from simulated and real data. Comparisons are made with histograms, kernel density estimation, and quantile–quantile plots. |
| Tipo: Journal Article |
Palavras-chave: Density probability plots; Distributions; Histograms; Kernel density estimation; Quantile–quantile plots; Statistical graphics; Research Methods/ Statistical Methods. |
| Ano: 2005 |
URL: http://purl.umn.edu/117517 |
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