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I am trying to do a simple comparison of summary statistics for two variables in R (econmath$act; and econmath$act0). In this chunk of code I create the variable econmath$act0:

library('wooldridge')
data(econmath)
econmath$actmiss<-ifelse(is.na(econmath$act),1,0)
econmath$act0<-ifelse(data$actmiss==1,0,data$act)

I want to compare summary statistics for econmath$act with econmath$act0. The only way I have found to compare these so far is using the st function from the vtable package. However, I would prefer a solution that can present them in the console. I have tried the following:

stargazer(summary(econmath$act),summary(econmath$act0),type="text")

But I get the following error message:

Error in objects[[i]]$zelig.call :
$ operator is invalid for atomic vectors

Is there a package/command that I can use that will output comparable summary statistics (on just two variables) to the console, rather than the viewer? I would like to be able to do this in stargazer if possible.

AKJ
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    Welcome to SO! It would be helpful to provide a reproducible dataset so others can help you. Run `dput(econmath)` and paste the output into your question so people can reproduce your data and help. – Shawn Hemelstrand Dec 31 '22 at 05:53
  • Note that sumtable/st can output to the console if you specify the out = 'return' option. This will return a data.frame. – NickCHK Mar 08 '23 at 21:11

1 Answers1

2

1. The data

First of all, you don't need to load an entire package to get one of its data sets, data has an argument package.

data(econmath, package = 'wooldridge')
str(econmath)
#> 'data.frame':    856 obs. of  17 variables:
#>  $ age     : int  23 23 21 22 22 22 22 22 22 21 ...
#>  $ work    : num  15 0 25 30 25 0 20 20 28 22.5 ...
#>  $ study   : num  10 22.5 12 40 15 30 25 15 7 25 ...
#>  $ econhs  : int  0 1 0 0 1 0 1 0 0 0 ...
#>  $ colgpa  : num  3.49 2.1 3.09 2.68 3.75 ...
#>  $ hsgpa   : num  3.35 3.22 3.31 3.98 3.89 ...
#>  $ acteng  : int  24 23 21 31 28 25 15 28 28 18 ...
#>  $ actmth  : int  26 20 24 28 31 30 19 30 28 19 ...
#>  $ act     : int  27 24 21 31 32 28 18 32 30 17 ...
#>  $ mathscr : int  10 9 8 10 8 10 9 9 6 9 ...
#>  $ male    : int  1 1 1 0 1 1 0 1 0 0 ...
#>  $ calculus: int  1 0 1 1 1 1 1 1 0 1 ...
#>  $ attexc  : int  0 0 1 0 0 1 0 1 1 0 ...
#>  $ attgood : int  0 0 0 1 1 0 1 0 0 1 ...
#>  $ fathcoll: int  1 0 0 1 0 0 0 1 0 0 ...
#>  $ mothcoll: int  1 1 1 1 1 1 0 1 1 0 ...
#>  $ score   : num  84.4 57.4 66.4 81.2 95.9 ...

Created on 2022-12-31 with reprex v2.0.2

2. A bug corrected.

There was a bug in the question's code, data$actmiss and data$act refer to a non-existing data set.
Also, in its first use, ifelse can be replaced by as.integer.

data(econmath, package = 'wooldridge')

econmath$actmiss <- as.integer(is.na(econmath$act))
econmath$act0 <- ifelse(econmath$actmiss == 1L, 0L, econmath$act)

Created on 2022-12-31 with reprex v2.0.2

3. The question.

The operator $ extracts a list member or data.frame column, use [ and the error is gone, see Difference between [ and [[.

In the code below I create a vector of columns of interest in order to make the code more readable. Then format the summaries with stargazer.

Aren't you looking for the second table? Instead of explicitly calling summary on the objects, argument summary gives the best output.

data(econmath, package = 'wooldridge')

econmath$actmiss <- as.integer(is.na(econmath$act))
econmath$act0 <- ifelse(econmath$actmiss == 1L, 0L, econmath$act)

cols <- c("act", "act0")
stargazer::stargazer(summary(econmath[cols]), type = "text")
#> 
#> =========================
#>    act act0      NA      
#> -------------------------
#> 1      act   Min. :13.00 
#> 2      act  1st Qu.:21.00
#> 3      act  Median :23.00
#> 4      act   Mean :23.12 
#> 5      act  3rd Qu.:25.00
#> 6      act   Max. :33.00 
#> 7      act    NA's :42   
#> 8      act0  Min. : 0.00 
#> 9      act0 1st Qu.:20.00
#> 10     act0 Median :23.00
#> 11     act0  Mean :21.99 
#> 12     act0 3rd Qu.:25.00
#> 13     act0  Max. :33.00 
#> 14     act0              
#> -------------------------
stargazer::stargazer(econmath[cols], summary = TRUE, type = "text")
#> 
#> =====================================
#> Statistic  N   Mean  St. Dev. Min Max
#> -------------------------------------
#> act       814 23.122  3.349   13  33 
#> act0      856 21.987  5.970    0  33 
#> -------------------------------------

Created on 2022-12-31 with reprex v2.0.2

Another two ways are

stargazer::stargazer(summary(econmath['act']),
                     summary(econmath['act0']),
                     type = "text")
#> 
#> =======================
#>   act NA      NA.1     
#> -----------------------
#> 1     act  Min. :13.00 
#> 2     act 1st Qu.:21.00
#> 3     act Median :23.00
#> 4     act  Mean :23.12 
#> 5     act 3rd Qu.:25.00
#> 6     act  Max. :33.00 
#> 7     act   NA's :42   
#> -----------------------
#> 
#> =========================
#>   act0  NA      NA.1     
#> -------------------------
#> 1      act0  Min. : 0.00 
#> 2      act0 1st Qu.:20.00
#> 3      act0 Median :23.00
#> 4      act0  Mean :21.99 
#> 5      act0 3rd Qu.:25.00
#> 6      act0  Max. :33.00 
#> -------------------------

stargazer::stargazer(econmath['act'],
                     econmath['act0'],
                     summary = TRUE,
                     type = "text")
#> 
#> =====================================
#> Statistic  N   Mean  St. Dev. Min Max
#> -------------------------------------
#> act       814 23.122  3.349   13  33 
#> -------------------------------------
#> 
#> =====================================
#> Statistic  N   Mean  St. Dev. Min Max
#> -------------------------------------
#> act0      856 21.987  5.970    0  33 
#> -------------------------------------

Created on 2022-12-31 with reprex v2.0.2

Rui Barradas
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