Week 07

Question 1

Numerical scales for measuring

Answer 1

Numerical value must identify scale on which measurement it made (days, metres, kg, degrees celcius)

Question 2

Non-numerical scales

Answer 2

Within a category:

• countable (quantity)
• in categories (male female)
• When we count the number of instances in a category, the result is discrete data

Question 3

Stevens levels of measurement

Answer 3

• Nominal
• Ordinal
• Interval
• Ratio scale

Question 4

Nominal scales

Answer 4

• Only categories (labels), not quantities

- Examples: gender, post codes, in health diagnostic criteria, illness or other factor

Question 5

Ordinal scales

Answer 5

Distinguish objects and events according to their ranking (high or low)
e.g. winner of running race first in speed (finishing first indicates more speed)

Question 6

Ordinal scales says NOTHING about …?

Answer 6

separation between ranks (difference between first and second place scores)

Question 7

Interval scales

Answer 7

Compared to ordinal, interval scales add constantly sized (i.e. equal) intervals between all points along the scale

Question 8

Interval scales hold a true zero or non true zero?

Answer 8

Not true

e.g. 0 in celcius and F do not mean no temperature

Question 9

Interval scales: Is doubling twice as much?

Answer 9

No. 100 degrees is not as hot as 50 degrees doubled

Question 10

Ratio scales, does it hold true zero?

Answer 10

Yes

Question 11

Ratio scales, is doubling REALLY doubling

Answer 11

Yes!

Question 12

Many physical measures such as length, weight, time, speed, heart rate, and economic measures are measured in _____ scales

Answer 12

ratio

Question 13

Categorical data…..

Answer 13

• Nominal and ordinal scales because they refer to membership of a category, either a group on a nominal scale (e.g. female) or a rank order position on an ordinal scale (e.g. distinction grade)
• Categorical data are mostly counted, but not quantities

Question 14

Continuous data…

Answer 14

• Interval and ratio scales

- countable and summary statistics such as averages (can say number of males and females, but not average gender)

Question 15

Discrete data…(count data)…?

Answer 15

• Counts the numbers of persons, places, things or events
• Expressed only as whole numbers, never fractions
• Number of people in a room, positive test results, births, marriages, deaths
• Because discrete data have equal intervals and true zero, can be analysed as ratio

Question 16

______ scales carry the most amount of information

Answer 16

ratio

Question 17

Categorical data: Ordinal scales…

Answer 17

• NOT true zero
• NOT equal intervals
• Rank order, lowest to highest
• Categorical information

Question 18

Categorical data: Nominal scales…

Answer 18

• NOT true zero
• NOT equal intervals
• NOT rank order, lowest to highest
• Categorical information

Question 19

Continuous data: Ratio scales…?

Answer 19

• true zero
• equal intervals
• rank order, lowest through to highest
• Categorical information

Question 20

Continuous data: Interval scales…?

Answer 20

• NOT true zero
• Equal intervals
• rank order, lowest to highest
• Categorical information

Question 21

Health science normally uses ___ scales

Answer 21

ratio