Topic 2 DV

Question 1

What two scientific goals make up Correlation research?

Answer 1

Description and Prediction

Question 2

What two scientific goals make up Experimental research?

Answer 2

Explanation and Control

Question 3

Define causation

Answer 3

One factor DIRECTLY affects another factor

Question 4

To show causation what must be demonstrated?

Answer 4

1. Changing the 1st thing produces change in the 2nd

2. There is no other cause for the change

Question 5

Define a population

Answer 5

Members of a specific group

Question 6

What is a study population defined by?

Answer 6

Defined by the purposes of the experiment

Question 7

Define a sample

Answer 7

Small subset of the population that represents the population

Question 8

How is a representative sample achieved?

Answer 8

Through random sampling where each member has equal chance of selection

Question 9

What is descriptive statistics?

Answer 9

Summarises the data collected from the sample

Question 10

What is inferential statisitcs?

Answer 10

Generalise from the sample to the population

Question 11

What two things must be considered when you can’t directly measure topic of interest?

Answer 11

1. Property of interest - what you are trying to measure e.g. intelligence
2. Dependent variable - a measurable value that must indirectly reflect the property of interest e.g. score on IQ test
   (the indirect measure is the operational definition of your property of interest)

Question 12

What is validity?

Answer 12

A dependent variable is valid if it measures what it’s supposed to

Question 13

What is a dependent variable?

Answer 13

A measurement taken
What is recorded
Depends on what the participant does

Question 14

What is a threat of validity?

Answer 14

Confounding

Poor Operational definition -> invalid dependent variable

Question 15

What is reliability?

Answer 15

A dependent variable is reliable if under the same conditions the same results are found and contains the minimum of measurement error

Question 16

True or false

If a measure lacks reliability it will also lack validity?

Answer 16

True

Question 17

What is bias?

Answer 17

A biased dependent variable is consistently inaccurate in one direction e.g. always high, always low

Question 18

What is the ceiling effect?

Answer 18

When a task is too easy that all the results are very high

Question 19

What is the floor effect?

Answer 19

When a task is too hard that all the results are very low

Question 20

Describe a nominal scale

Answer 20

• Categorises data WITHOUT ORDERING

- Numbers substitute for names e.g. gender, 1=F 2=M

Question 21

Describe an ordinal scale

Answer 21

• Categorises data and ORDERS
• Bigger means more
• distance between the points is NOT CONSIDERED EQUAL
  e. g. placing 1st 2nd 3rd

Question 22

Describe an interval scale

Answer 22

• Categorises, orders, and establishes an equal unit of measurement in the scale
• We KNOW VALUE BETWEEN POINTS on the scale
• Distance between points on the scale considered equal
  e. g. degrees celsius

Question 23

Describe a ratio scale

Answer 23

• Categorises, orders, and establishes equal unit in the scale
• CONTAINS A TRUE ZERO POINT
• Allows ratio statements e.g. ‘twice as big’