Chapter 1

Question 1

what is R used for

Answer 1

R is used for data manipulation, statistics, and

graphics.

Question 2

getwd ()

Answer 2

get your user name # Set working directory

Question 3

numbers vs. character strings

Answer 3

# numbers vs. character strings
7 # The number 7
"7" # The character for the numeral 7.

Question 4

scales

Answer 4

Scales
Nominal categories
 Ordinal categories, rank
 Interval categories, rank, equal, interval
 Ratio categories, rank, equal, interval, true zero point
Scales Examples
 Nominal types of flowers, vote/abstain
 Ordinal socioeconomic status (S.E.S.), class rank
 Interval time (in the abstract with no ending or beginning)
 Ratio age, weight, height, time to complete a task

Question 5

scale examples

Answer 5

Scales Examples
 Nominal types of flowers, vote/abstain
 Ordinal socioeconomic status (S.E.S.), class rank
 Interval time (in the abstract with no ending or beginning)
 Ratio age, weight, height, time to complete a task

Question 6

Categorical variables

Answer 6

A categorical variable
has values that function as labels rather than as
numbers.

Question 7

Continuous variables

Answer 7

A continuous variable

has numeric values such as 1, 2, 3.14, -5, etc.

Question 8

Types

Answer 8

Distinct categories that you use in classifying
variables. Example: “dogs” and “cats” for the
variable animal.

Question 9

Tokens

Answer 9

The number of observed instances for each
type. Example: the individual dogs and cats that are
counted.

Question 10

Population

Answer 10

An entire set of possible entities or

values.

Question 11

Sample

Answer 11

A portion of a population chosen to

represent that population.

Question 12

Distribution

Answer 12

A description of how data are
distributed across the possible values of a
variable.

Question 13

 Bar plot:

Answer 13

A picture of the distribution of a variable.

Question 14

Reliability

Answer 14

Also known as replicability, that is
whether performing the same experiment multiple
times, or performing the same analysis on
multiple samples will yield the same results.

Question 15

Validity

Answer 15

Your results are not valid unless you use the
appropriate analysis for the data you have and the
analysis answers the questions you have set out
to research.