Week 2

Question 1

Variable

Answer 1

A variable is any observable feature of the natural world

Question 2

DATUM

Answer 2

A datum, or observation, is any one record of the state of a variable.

Question 3

DATASET

Answer 3

Any collection of observations made on a variable is a data set

Question 4

POPULATION

Answer 4

The set of all possible observations on a variable is the population

Question 5

FINITE

POPULATION

Answer 5

Populations can be either finite or infinite. Finite populations have a finite, countable
number of elements and can, in theory at least, be completely sampled.

Question 6

INFINITE

POPULATION

Answer 6

Infinite populations have an infinite number of elements and can never be completely
sampled.

Question 7

SAMPLE

Answer 7

Large and infinite populations cannot be observed in their entirety, so we take only
(nearly always randomly) a sample (sub)set of observations from a population.

Question 8

PARAMETER

Answer 8

A parameter is some characteristic of the distribution of the values of a variable in a
population.

Question 9

STATISTIC

Answer 9

The term “statistic” is used in two ways: to refer to the entire body of procedures for
dealing with data; or to refer to estimates of population parameters based on samples.

Question 10

Mode

Answer 10

most common value

Question 11

Median

Answer 11

middle value

Question 12

Mean

Answer 12

average value

Question 13

Sample mean symbol

Answer 13

⨱

Question 14

Population mean symbol

Answer 14

μ

Question 15

Variance

Answer 15

spread of distribution

Question 16

Skewness

Answer 16

skew of peak distribution to one side of the mean

Question 17

Kurtosis

Answer 17

peakedness or flatness of distribution

Question 18

VARIANCE (s2

Answer 18

measures the dispersion of data around their

mean value

Question 19

NORMAL DISTRIBUTION

Answer 19

a symmetric distribution, often called a
bell-curve which describes many parameters of the natural world,
e.g. height, weight, test scores in a very large class

Question 20

STANDARD DEVIATION

Answer 20

a measure of dispersion in the

data, standardised relative to the mean

Question 21

SKEWNESS

Answer 21

measures the extent to which the distribution is

“pushed” to either side of the mean

Question 22

Mesokurtic

Answer 22

meso – middle, intermediate, halfway

Question 23

Leptokurtic

Answer 23

lepto – small, fine, thin, delicate

Question 24

Platykurtic

Answer 24

platy – broad, flat

Question 25

NOMINAL/CLASSIFICATION variables

Answer 25

variables can be classified into named groups

e.g. sex, colour, habitat type etc.

Question 26

ORDINAL/RANKING variables

Answer 26

can be ranked in order e.g. social position,

size-class, education level etc.

Question 27

NUMERICAL/QUANTITATIVE variables

Answer 27

can be enumerated or quantified

(counted or measured), e.g. height, weight etc