marginal total in tables

Question

I have a data frame with a number of infections identified from clinical isolates at different dates.

So far I have organised the data into a shape that I want to start working with. I am trying to prepare a series of tables of tables for the descriptive statistics of the report.

I have been using ftable and get the following:

onset.types <- ftable(SAB$Onset,SAB$MRSA.Type,year(SAB$Collection.Date))                              2005 2006 2007 2008 2009 2010  Community                     454  472  512  499  525  512           AUS-2/3-like         28   23   27   29   32   38           EMRSA-15-like         9    4    4    9    8    8           nmMRSA               40   47   53   39   64   60           Other mMRSA           1    3    3   11    5    9           unclassified MRSA     0    2    0    0    1    1 Hospital                      163  163  156  164  149  165           AUS-2/3-like         31   33   27   31   29   28           EMRSA-15-like         3    8    5    9    4    3           nmMRSA               10    9   13   17   13   12           Other mMRSA           5    1    6    2    3   10           unclassified MRSA     2    0    1    0    0    0 

Two questions:

1: How would I calculate marginal totals

2: Is there an easy way to calculate percentages as well as counts again with marginal totals

I have tried epitools and I did not find it as useful as I would have liked.

Many thanks.

Answer 1

To add margins, use addmargins()

addmargins(table(state.division, state.region))                     state.region state.division       Northeast South North Central West Sum   New England                6     0             0    0   6   Middle Atlantic            3     0             0    0   3   South Atlantic             0     8             0    0   8   East South Central         0     4             0    0   4   West South Central         0     4             0    0   4   East North Central         0     0             5    0   5   West North Central         0     0             7    0   7   Mountain                   0     0             0    8   8   Pacific                    0     0             0    5   5   Sum                        9    16            12   13  50 

To calculate percentages, use prop.table()

prop.table(table(state.division, state.region))                     state.region state.division       Northeast South North Central West   New England             0.12  0.00          0.00 0.00   Middle Atlantic         0.06  0.00          0.00 0.00   South Atlantic          0.00  0.16          0.00 0.00   East South Central      0.00  0.08          0.00 0.00   West South Central      0.00  0.08          0.00 0.00   East North Central      0.00  0.00          0.10 0.00   West North Central      0.00  0.00          0.14 0.00   Mountain                0.00  0.00          0.00 0.16   Pacific                 0.00  0.00          0.00 0.10