Using R Flashcards
What is the order of operation of the following numerical operators? / division \+ summation - subtraction * multiplication ^ power
^ power * multiplication / division \+ summation - subtraction
What is the order of operation of the following numerical operators? / division \+ summation - subtraction * multiplication ^ power
^ power * multiplication / division \+ summation - subtraction
!=
What is the meaning of these two logical operators:
- Not equal to
- Equal to
In R, what does | mean?
OR
What is the default number of decimal places for the round() function?
0
Name the three types of variables in R
- Numeric
- Character
- Logical
In R, what is the assignment operator?
In R, a variable can begin with a non-alpha-numeric character?
Only a period, but not other non-alpha-numeric characters
In R, what is the name for a variable that contains more than one variable?
A vector
In R, the values within a vector recalled what?
Elements
In R, how would you use logical statements to call individual elements from a vector?
Like this:
vector name [vector name <0.90]
Which pulls all the elements in that vector that are less than 0.9
In R, what does | mean?
OR
What is the default number of decimal places for the round() function?
0
In R, what function do you use to load a package
library()
In R, what is the assignment operator?
In R, a variable can begin with a non-alpha-numeric character?
Only a period, but not other non-alpha-numeric characters
In R, what is the name for a variable that contains more than one variable?
A vector
In R, the values within a vector recalled what?
Elements
In R, how would you use logical values to call individual elements from a vector?
like this:
vector name[c(TRUE, TRUE, FALSE)]
Which means it won’t call the third element of the vector
In R, if you want to pull/inspect a specific variable in a data frame, which symbol do you use?
$
As in:
dataframe&examplevariable
Factor variables are nominal categorical variables, T/F
Provide an example
TRUE
Eye colour or sex
In R, what function do you use to load a package
library()
In R, what function do you use to install a package
install.packages()
In R, what function do you use to load a dataframe
load()
In R, what function do you use to convert factor variables to numeric type (which you might do for the purposes of a computation)
as.numeric()
When dummy coding in R, what is the name of the category that will have 0 in all three dummy variables?
The ‘reference category’
When you are investigating group difference…
and there is only one axis along which groups can differ (ie hair colour)
What is the label you give to this type of design?
A ‘one-way’ etc etc design
as in a ‘One-way between-subjects design’
When you are investigating group difference…
and the groups are independent…
What is the label you give to this type of design?
A etc etc ‘between-subjects’ design
as in a ‘One-way between-subjects design’
What does ANOVA stand for?
Analysis of Variance
What is the null hypothesis (H0) of an ANOVA?
That the means for each group are the same
If you are comparing the means of five groups on a continuous measure, how many degrees of freedom do you have?
Four
Because in this instance:
df = k - 1
Where k = number of groups
What is a linear contrast?
A set of weights that sum to zero?
What is the name of a set of weights that sum to zero?
A linear contrast
