choosing a statistical test

Question 1

3 factors used to decide on the statistical test

Answer 1

1. whether researcher is looking for difference or correlation
2. (if test of difference) what experimental design is being used
3. level of measurement

Question 2

describe decision 1: difference or correlation?

Answer 2

• obvious from wording of hypothesis

Question 3

describe decision 2: experimental design? (if test of difference)

Answer 3

• 3 types of experimental design: repeated measures, independent groups & matched pairs
• repeated measures & matched pairs = related designs
• independent groups = unrelated design

Question 4

draw the statistical test grid

Answer 4

pg. 70 of year 2 textbook

Question 5

what 3 levels of measurement is there

Answer 5

1. nominal data
2. ordinal data
3. interval data

Question 6

what are the levels of measurements

Answer 6

all quantitative data

Question 7

describe nominal data

Answer 7

• data in form of categories
• eg. ‘yes’ in one group & ‘no’ in the other
• discrete data = one item can only appear in one of the categories
• can have more than 2 groups

Question 8

describe ordinal data

Answer 8

• data is ordered
• eg. asking everyone to rate something on a scale 1-10
• doesn’t have equal intervals between each unit
• lacks precision (based on subjective opinion not objective measures)
• raw scores converted to ranks, which are used in the calculation

Question 9

describe interval data

Answer 9

• based on numerical scales which include units of equal, precisely defined size
• eg. stopwatch, thermometer, weighing scales
• public scales of measurement which produce data based on accepted units of measurement
• most precise & sophisticated form of data