R: Summary Statistics

summary-statistics {collapse} | R Documentation

## Summary Statistics

### Description

collapse provides the following functions to efficiently summarize and examine data:

- `qsu`, shorthand for quick-summary, is an extremely fast summary command inspired by the (xt)summarize command in the STATA statistical software. It computes a set of 7 statistics (nobs, mean, sd, min, max, skewness and kurtosis) using a numerically stable one-pass method. Statistics can be computed weighted, by groups, and also within-and between entities (for multilevel / panel data).

- `qtab`, shorthand for quick-table, is a faster and more versatile alternative to `table`. Notably, it also supports tabulations with frequency weights, as well as computing a statistic over combinations of variables. 'qtab's inherit the 'table' class, allowing for seamless application of 'table' methods.

- `descr` computes a concise and detailed description of a data frame, including (sorted) frequency tables for categorical variables and various statistics and quantiles for numeric variables. It is inspired by `Hmisc::describe`, but about 10x faster.

- `pwcor`, `pwcov` and `pwnobs` compute (weighted) pairwise correlations, covariances and observation counts on matrices and data frames. Pairwise correlations and covariances can be computed together with observation counts and p-values. The elaborate print method displays all of these statistics in a single correlation table.

- `varying` very efficiently checks for the presence of any variation in data (optionally) within groups (such as panel-identifiers). A variable is variant if it has at least 2 distinct non-missing data points.

### Table of Functions

Function / S3 Generic |  | Methods |  | Description
`qsu` |  | `default, matrix, data.frame, pseries, pdata.frame` |  | Fast (grouped, weighted, panel-decomposed) summary statistics
`qtab` |  | No methods, for data frames or vectors |  | Fast (weighted) cross tabulation
`descr` |  | No methods, for data frames or lists of vectors |  | Detailed statistical description of data frame
`pwcor` |  | No methods, for matrices or data frames |  | Pairwise (weighted) correlations
`pwcov` |  | No methods, for matrices or data frames |  | Pairwise (weighted) covariances
`pwnobs` |  | No methods, for matrices or data frames |  | Pairwise observation counts
`varying` |  | `default, matrix, data.frame, pseries, pdata.frame, grouped_df` |  | Fast variation check

### See Also

Collapse Overview, Fast Statistical Functions

[Package collapse version 1.8.6 Index]