Statistics revision 1

Question 1

What is statistics?

Answer 1

Method for organising, summarising, and interpreting data

Question 2

Define population

Answer 2

The entire set of individuals

Question 3

Define sample

Answer 3

Group selected from the population to study

Question 4

Why use a sample?

Answer 4

As populations are very large making it impossible to study

Question 5

What characteristic describes a sample?

Answer 5

Statistic

Question 6

What characteristic describes a population?

Answer 6

parameter

Question 7

What are sample statistics representative of?

Answer 7

the corresponding population

Question 8

What is a sampling error?

Answer 8

Difference between a sample statistic and population parameter

Question 9

Describe descriptive statistics

Answer 9

the method which organises, summarises and simplifies data

Question 10

Describe inferential statistics

Answer 10

uses sample data to make inferences about a population

Question 11

What is a variable?

Answer 11

a characteristic or condition that changes

Question 12

Sample results are…

Answer 12

generalised to the corresponding population

Question 13

What is the correlational method?

Answer 13

two variables observed to determine a relationship

Question 14

What are the limitations of correlational methods?

Answer 14

Cannot explain cause and effect relationships.

Question 15

Describe experimental methods

Answer 15

One variable is manipulated while observing another variable to establish cause and effect.

Question 16

What is an independent variable?

Answer 16

Variable that is manipulated. Antecedent variable manipulated prior to observing dependent variable.

Question 17

What is a dependent variable?

Answer 17

The variable observed to assess the affect of the treatment

Question 18

What is the difference between the correlational method and the experimental method

Answer 18

Experimental method = one variable is measured

Correlational method = both variables are measured

Question 19

Explain the control condition

Answer 19

Some participants received no treatment or a placebo/neutral treatment

Question 20

purpose of control condition….

Answer 20

baseline for comparison

Question 21

Describe the experimental condition

Answer 21

participants receive the experimental treatment

Question 22

Explain the concept of control

Answer 22

The researcher exercises control so that extraneous or confounding variables do not influence the relaionship

Question 23

What are confounding variables

Answer 23

variables you are not researching that may affect outcomes

Question 24

types of confounding variables

Answer 24

Situational, participant, experimenter, and demand characteristics e.g conforming to test conditions, social desirability

Question 25

What is random assignment?

Answer 25

Each participant has an equal chance of being assigned to either condition.

Question 26

Purpose of random assignment

Answer 26

Distributes participant characteristics evenly, so that both groups do differ greatly in terms of gender, age, intelligence etc.

Question 27

What are environmental variables?

Answer 27

time of day, light, dark, weather, hot, cold etc

Question 28

What are participant variables?

Answer 28

age, gender, intelligence

Question 29

What is a matching condition?

Answer 29

equivalent groups or environments e.g all groups have 40% females and 60% males.

Question 30

Holding them constant means…

Answer 30

e.g researchers might only use 10 year old boys - thereby holding age and gender constant.

Question 31

What is a construct?

Answer 31

internal attributes which can not be directly observed e.g Anxious, intelligence, hungry, sad

Question 32

Operational definition is

Answer 32

Defining a concept or construct by the operations used to represent or measure it e.g intelligence measured by performance tests

Question 33

What is a discrete variable?

Answer 33

has no intermediate values. e.g number of children, number on a dice, number of students present each day. Impossible to observe an intermediate value

Question 34

What is a continuous variable?

Answer 34

An infinite number of possible values that fall between values. e.g height, weight, time.

Question 35

What is the nominal scale?

Answer 35

Categorical - labels observations e.g race, gender, occupation

Question 36

What is the ordinal scale?

Answer 36

Categories ordered by rank - such as 1st, 2nd, 3rd. Small, medium, large. Upper, middle, lower

Question 37

What is an interval scale?

Answer 37

metric - ordered exactly the same e.g inch, cm, degree

Question 38

What is a ratio scale?

Answer 38

metric - has a zero point that is not arbitrary e.g gallons with zero gallons being empty.

Question 39

What is a mediating variable?

Answer 39

Explains how two variables are related

Question 40

What is a moderating variable?

Answer 40

affects the strength and direction of that relationship

Question 41

What is the mean?

Answer 41

is the sum of all scores divided by the number of all scores

Question 42

The median is…

Answer 42

the central number or midpoint of the data set of scores

Question 43

The mode is

Answer 43

the number that appears the most in the data set of scores

Question 44

What is the standard deviation?

Answer 44

is a measure of how dispersed the data is in relation to the mean

Question 45

What is the effect size?

Answer 45

Effect size is a quantitative measure of the magnitude of the experimental effect. The larger the effect size the stronger the relationship between two variables.

Question 46

What is operationalism?

Answer 46

Representing constructs by a specific set of operations