10 I
10.1 IDE
Integrated Development Environment: a program that serves as a text editor, file manager, and provides functions to help you read and write code. RStudio is an IDE for R.
10.2 %in%
The match operator, a binary operator that returns a logical vector indicating if there is a match or not for its left operand.
10.3 independent variable
A variable whose value is assumed to influence the value of a dependent variable.
This term is often used in an experimental context. In a regression context, this is equivalent in meaning to predictor variable.
10.4 index
The number that represents an element's location in a vector.
For example, the index of the letter E
in the vector LETTERS
is 5.
This can also refer to the main page of a website. For example, the address for the main page of the glossary is technically https://psyteachr.github.io/glossary/index.html
(but https://psyteachr.github.io/glossary/
invisibly directs you to the index page).
10.5 inferential
Statistics that allow you to make predictions about or comparisons between data (e.g., t-value, F-value, rho)
Contrast with descriptive statistics.
10.6 inner-join
A mutating join that returns all the rows that have a match in the other table.

Figure 10.1: Inner Join
Table X | Table Y | ||||||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
|
# a columns come first
data <- inner_join(a, b, by = "id")
id | x.x | y | x.y |
---|---|---|---|
Order is not important for inner joins, but does change the order of columns in the resulting table.
# b columns come first
data <- inner_join(b, a, by = "id")
x.x | id | x.y | y |
---|---|---|---|
See joins for other types of joins and further resources.
10.7 integer
A data type representing whole numbers.
In R, you specify that a number is an integer by adding an L at the end, like 1L
, -36L
, or 100L
.
10.8 intercept
Also referred to as y-intercept, this is a constant corresponding to the value of the \(y\) variable (in a regression context, the response variable) when all predictor variables are set to zero.