Using R

Question 1

What is the order of operation of the following numerical operators?
/ division
\+ summation 
- subtraction 
* multiplication 
^ power

Answer 1

^ power
* multiplication 
/ division
\+ summation 
- subtraction

Question 2

What is the order of operation of the following numerical operators?
/ division
\+ summation 
- subtraction 
* multiplication 
^ power

Answer 2

^ power
* multiplication 
/ division
\+ summation 
- subtraction

Question 3

!=

What is the meaning of these two logical operators:

Answer 3

• Not equal to

- Equal to

Question 4

In R, what does | mean?

Answer 4

OR

Question 5

What is the default number of decimal places for the round() function?

Answer 5

0

Question 6

Name the three types of variables in R

Answer 6

1. Numeric
2. Character
3. Logical

Question 7

In R, what is the assignment operator?

Question 8

In R, a variable can begin with a non-alpha-numeric character?

Answer 8

Only a period, but not other non-alpha-numeric characters

Question 9

In R, what is the name for a variable that contains more than one variable?

Answer 9

A vector

Question 10

In R, the values within a vector recalled what?

Answer 10

Elements

Question 11

In R, how would you use logical statements to call individual elements from a vector?

Answer 11

Like this:

vector name [vector name <0.90]

Which pulls all the elements in that vector that are less than 0.9

Question 12

In R, what does | mean?

Answer 12

OR

Question 13

What is the default number of decimal places for the round() function?

Answer 13

0

Question 14

In R, what function do you use to load a package

Answer 14

library()

Question 15

In R, what is the assignment operator?

Question 16

In R, a variable can begin with a non-alpha-numeric character?

Answer 16

Only a period, but not other non-alpha-numeric characters

Question 17

In R, what is the name for a variable that contains more than one variable?

Answer 17

A vector

Question 18

In R, the values within a vector recalled what?

Answer 18

Elements

Question 19

In R, how would you use logical values to call individual elements from a vector?

Answer 19

like this:

vector name[c(TRUE, TRUE, FALSE)]

Which means it won’t call the third element of the vector

Question 20

In R, if you want to pull/inspect a specific variable in a data frame, which symbol do you use?

Answer 20

$

As in:
dataframe&examplevariable

Question 21

Factor variables are nominal categorical variables, T/F

Provide an example

Answer 21

TRUE

Eye colour or sex

Question 22

In R, what function do you use to load a package

Answer 22

library()

Question 23

In R, what function do you use to install a package

Answer 23

install.packages()

Question 24

In R, what function do you use to load a dataframe

Answer 24

load()

Question 25

In R, what function do you use to convert factor variables to numeric type (which you might do for the purposes of a computation)

Answer 25

as.numeric()

Question 26

When dummy coding in R, what is the name of the category that will have 0 in all three dummy variables?

Answer 26

The ‘reference category’

Question 27

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?

Answer 27

A ‘one-way’ etc etc design

as in a ‘One-way between-subjects design’

Question 28

When you are investigating group difference…

and the groups are independent…

What is the label you give to this type of design?

Answer 28

A etc etc ‘between-subjects’ design

as in a ‘One-way between-subjects design’

Question 29

What does ANOVA stand for?

Answer 29

Analysis of Variance

Question 30

What is the null hypothesis (H0) of an ANOVA?

Answer 30

That the means for each group are the same

Question 31

If you are comparing the means of five groups on a continuous measure, how many degrees of freedom do you have?

Answer 31

Four

Because in this instance:

df = k - 1

Where k = number of groups

Question 32

What is a linear contrast?

Answer 32

A set of weights that sum to zero?

Question 33

What is the name of a set of weights that sum to zero?

Answer 33

A linear contrast