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Research Methods 1. Levels of Measurement. Self Assessment On completion of this session you should comprehend:. The differences between subjective measures and objective measures The nature of interval, ratio, nominal and ordinal measures. From research question to data collection.
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Research Methods 1 Levels of Measurement
Self AssessmentOn completion of this session you should comprehend: • The differences between subjective measures and objective measures • The nature of interval, ratio, nominal and ordinal measures
From research question to data collection • Research hypothesis - operationalisation • What are you measuring and how are you going to measure it? • Independent and dependent variables
Variables? • Parameters/Properties that vary • Independent variable - what is the experimenter going to manipulate? • Dependent variable - what is the outcome that is to be measured?
Independent and Dependent Variables • The investigation of the effect of ultrasound therapy on pain intensity levels. • The investigation of the effect of aerobic exercise on perceived mood state.
Definition of measurement “All any measurement is is a parameter chosen to represent the concept.” Dane (1990)
Types of measurements • Objective - measurement of physical quantities and qualities using measurement equipment e.g. tape measure, electric weighing scales, goniometry • Subjective - ratings or judgements by humans of quantities and qualities e.g. rating ROM by eyeball estimation • Uses?
Types of measurements • Qualitative; A ‘quality’ of the subject e.g. gender, exam grade achieved etc. A characteristic or type not a measured amount. • Quantitative; A ‘quantity’ measured with numbers each number representing a measurement.
Qualitative Nominal Ordinal Quantitative Discrete Continuous Interval Ratio Types and Levels of measurements
Levels of Measurement • Nominal e.g. religion, eye colour • Ordinal e.g. age groups • Interval e.g. temperature (oC), intelligence • Ratio e.g. temperature (Kelvin), heart rate
The Parameter or the measurement? • Continuous scale Ratio level-Discrete Height (m) • Ordinal scale Height categories: short, average and tall • Nominal scale Height Grouping: < 1.2m > 1.7 m 1.2m < 1.50m 1.5m < 1.7m
Exercises • Identify one Qualitative measure and one Quantitative measure useful in your practice. • Identify one parameter from each level of measurement useful in your practice.
Exercises • Identify the level of measurement used in the journal articles chosen • Discuss the appropriateness of that measure • Suggest an alternative Level of Measurement