STATA MEAN BY GROUP UPDATE
STATA MEAN BY GROUP FULL

The codes will generate a table in StataвЂ™s output window like this: You only need to modify the first two lines to suit your data. The following codes are used for unpaired data.

One usage of unpaired data is the first step of HeckmanвЂ™s two-step procedure, in which two groups of observations (i.e., the group that will be selected into the second step and the group that will not be selected into the second step) are stacked vertically in the dataset. The above example is unpaired data, i.e., suspect firm-years and other firm-years are not 1-to-1 or 1-to-m matched. The codes vary between unpaired (i.e., unmatched) data and paired data. I write Stata codes to streamline the process.

STATA MEAN BY GROUP UPDATE

It is even more struggling that you have to repeat the tedious process every time you update your sample. However, it is time-consuming to glean numbers from the output of these Stata commands and place them in a table. We have an example where we use several techniques introduced earlier for automation: loops, levelsof, and using matrices to store results.Sometimes we may want to produce the following table to compare the mean and median of two groups:ДЇirst of all, please refer to this post to see Stata commands to test equality of mean and median. Merge 1:1 id sector using `f', keepusing(`v') We merged the master file with the 1st file a1 and kept the 1st variable b1 we then merged the last file with the 2nd file a2 and kept the 2nd variable b2. What we did below is using word to store the locations of each string in local macros, merged the files and kept the variables vertically. Replace residuals = `temp' if group = `x' What we did below is creating a temporary variable temp that stored the residuals from regressions within each group. Tempvar assigns names to the specified local macro that may be used as temporary variables in a program. UCLA: Statistical Consulting Group, How Can I Access Information Stored after I Run a Command in Stata (Returned Results)? | Stata FAQ tempvar Outside loops, levelsof can display the unique values of a variable.

ttest writing_gpa if writing_level = `x', by(gender) In loops, levelsof is useful to store the values of a variable in a local macro for later use by specifying the local() option. We can use Stata system variables to obtain coefficients and standard errors: To use the matrices later, we need to first store the matrices: To list the matrices of stored results, we can Predicted probabilities on samples used in the previous estimation outreg2 using myfile, adds(F-test, r(F), Prob > F, r(p)) replace twoway (lfitci mpg weight) (scatter mpg weight), note(R-squared =`r2')ДЄdding stats from postestimation in tables In order to be able to use the mean of mpg later, we can: The results will be lost the next time you run another r-class command. LetвЂ™s review some examples below where we use the stored results for various purposes.

STATA MEAN BY GROUP FULL

Which gives us the full lists of the results that the command regress offers. To see what the result lists actually look like, try typing Matrices: e(b) coefficient vector and e(V) varianceвЂ“covariance matrix of the estimates (VCE)ДЇunctions: the only function existing is e(sample), which evaluates to 1 (true) if the observation was used in the previous estimation and to 0 (false) otherwise. If we need to store the returned results, we need to use a macro. Results will be replaced the next time you execute another command of the same class. N-class commands that do not store in r(), e(), or s()Д¬-class system parameters and settings that store in c()Д¬ommands producing statistical results are either r-class or e-class: e-class for estimation results and r-class otherwise.ДЇollowing the r-class or e-class commands, we can obtain all the stored results of a command by typing return list or ereturn list respectively. S-class parsing commands that store results in s() used by programmers R-class general commands that store results in r()Д®-class estimation commands that store results in e() There are five classes of Stata commands: Results of calculations are stored by Stata commands so that they can be accessed in other commands and calculations later. Stored Results r-class and e-class commands

Stata mean by group