levels of measurement

Question 1

nominal data

Answer 1

• represented in categories
• e.g. ‘yes’ one group, ‘no’ other group
• discrete. one item can only appear in one category.

Question 2

ordinal data

Answer 2

data ordered in some way.
e.g. how much do you like psychology on a scale of 1 to 10.
doesn’t have equal intervals between each unit.

Question 3

ordinal data- issues

Answer 3

lacks precision. based on subjective opinion rather than objective measures.
questionnaires etc. measure psychological constructs. e.g. IQ test, questions derived from view of what constitutes intelligence not universal measurement.
not used in statistical testing. raw scores converted to ranks that are used in calculation.

Question 4

interval data

Answer 4

based on numerical scales that include units of equal, precisely defined size.
e.g. stopwatch, thermometer or weighing scales.

Question 5

interval data- strengths

Answer 5

most precise and sophisticated form of data in psychology.

Question 6

parametric tests

Answer 6

related t-test, unrelated t-test and Pearson’s r.
more powerful and robust than other tests.
1. interval data. actual scores used.
2. normal distribution.
3. homogeneity of variance.