What is Xtabs?

What is Xtabs?

xtabs() is the numerical version of barchartGC() . You use it when you want to study. the distribution of one factor variable; the relationship between two factor variables.

What does Xtabs in R do?

xtabs. The xtabs( ) function allows you to create crosstabulations using formula style input. If a variable is included on the left side of the formula, it is assumed to be a vector of frequencies (useful if the data have already been tabulated).

What is Ftable in R?

ftable returns an object of class “ftable” , which is a matrix with counts of each combination of the levels of variables with information on the names and levels of the (row and columns) variables stored as attributes “row. vars” and “col. vars” .

How do you make a contingency table in R?

We can create a custom contingency table in R using the following ways:

1. Using Columns of a Data Frame in a Contingency Table.
2. Using Rows of a Data Frame in a Contingency Table.
3. By Rotating Data Frames in R.
4. Creating Contingency Tables from Matrix Objects in R.

How do you subset in R?

So, to recap, here are 5 ways we can subset a data frame in R:

1. Subset using brackets by extracting the rows and columns we want.
2. Subset using brackets by omitting the rows and columns we don’t want.
3. Subset using brackets in combination with the which() function and the %in% operator.
4. Subset using the subset() function.

What is prop table in R?

The prop. table() is a built-in R function that expresses the table entries as Fraction of Marginal Table. table(), the values in each cell are divided by the sum of the 4 cells. If you require proportions across rows or down columns, all you need to do is add the margin argument.

What is a flat table in R?

A “flat table” (ftable object) is an alternate representation for a multiway table, as would be produced by table or tapply. Instead of a multiway array the data is stored in a two dimensional array and the table’s dimnames with names are replaced by the the attributes row. vars and col. vars.

What is the null hypothesis for a cross tabulation?

For a 2×2 table, the null hypothesis may equivalently be written in terms of the probabilities themselves, or the risk difference, the relative risk, or the odds ratio. In each case, the null hypothesis states that there is no difference between the two groups.

When to use the xtabs function in R?

The xtabs () function creates contingency tables in frequency-weighted format. Use xtabs () when you want to numerically study the distribution of one categorical variable, or the relationship between two categorical variables. Categorical variables are also called “factor” variables in R.

Which is the summary method for xtabs objects?

There is a summary method for contingency table objects created by table or xtabs (*, sparse = FALSE), which gives basic information and performs a chi-squared test for independence of factors (note that the function chisq.test currently only handles 2-d tables).

How to use xtabs ( ) to calculate frequencies?

The xtabs() function in R allows you to quickly calculate frequencies for one or more variables. It uses the following basic syntax: xtabs(~variable_name, data=data) where: variable_name: The variable that you’d like to calculate the frequencies for. data: The name of the data frame that the variable comes from.

How to create a contingency table using xtabs?

Using a formula interface, xtabs () can create a contingency table, (also a “sparse matrix”), from cross-classifying factors, usually contained in a data frame. Answers to the exercises are available here.

What is Xtabs? xtabs() is the numerical version of barchartGC() . You use it when you want to study. the distribution of one factor variable; the relationship between two factor variables. What does Xtabs in R do? xtabs. The xtabs( ) function allows you to create crosstabulations using formula style input. If a variable is…