SCIENTIFIC RESEARCH PROCESS Levels of Measurement

Goals of this Presentation At the end of this presentation, you will be able to:  Discuss differences that relate to levels of measurement  Distinguish between continuous and concrete variable measures

Levels of Measurement Remember the Science Research Process is a cycle Scientific Research Steps

Levels of Measurement Scientific Research Process  Systematic Steps build on each other  Adds to the body of knowledge about a problem  Identifies solutions to a problem And/Or  Evaluates effectiveness of a solution

Levels of Measurement Recall definition of Variables  Characteristics of elements that can be  Measured  Have multiple values  Used in hypotheses of theories  Used in developing statistics

Levels of Measurement Variable Measures Differ by Many Factors  Number of values may be finite or theoretically infinite  Values may or may not be able to be placed in a ranked order  Ranked values may or may not have equal units between values  There may or may not be a real zero value

Levels of Measurement Variable Categories Relate to Number of Possible Values  Continuous – in principle assume an infinite number of values  Examples: Age Temperature Percentages  Discrete – only a finite number of values  Examples: Number of people Yes/No responses Gender

Discrete v Continuous  Discrete  Continuous

Levels of Measurement Variable Categories Relate to Whether Values can be Put in Rank Order  Continuous Variables: Values can be ranked  Example: Age, 1<2<3……..  Discrete Variables: Values cannot be ranked  Example: Yes may have no higher value than no

Levels of Measurement Continuous Variable Categories Relate to Whether there is an Equal Unit Between Values  Likert scales do not have standard units.  You cannot say that the distance between very much disagree and disagree = the same distance as between very much agree and agree  Age has standard units: 12 months between each age value Very much agree – agree – neutral – disagree – very much disagree

Levels of Measurement Continuous Variable Categories Relate to Whether there is a Real Zero Value  Does not have an absolute zero: temperature  Two scales used for temperature, each with a different values for standards. There is no measure for no temperature  Does have absolute zero: age. Zero = not born Fahrenheit Freezing: 32° Boiling: 212° Celsius Freezing: 0° Boiling: 100°

Levels of Measurement Levels of Measures From lowest to highest sophistication:  Nominal  Ordinal  Interval  Ratio Acronym: NOIR

Levels of Measurement Nominal Level  Discrete Categories, for example  Male/Female  Yes/No  Numbers have no specific meaning, such as  Room Numbers

Levels of Measurement Ordinal Level  Continuous, but may be considered discrete  Values can be ranked  Units between the values differ  Examples  Likert scales, such as Strongly disagree – Disagree – neutral – Agree – Strongly agree

Example Ordinal Level: Rank Order Strongly disagree Disagree Neutral Agree Strongly agree

Example Ordinal Level: Rank Order Strongly disagree Disagree Neutral Agree Strongly agree Space between values differs and is not quantifiable

Levels of Measurement Interval Level  Continuous, but may be considered discrete  Intervals between elements are the same  Arbitrary zero point  Examples Temperature IQ

Example of Interval Data: Temperature Fahrenheit  Freezing: 32°  Boiling: 212° Celsius  Freezing: 0°  Boiling: 100°

Levels of Measurement Ratio Level  Continuous, but may be considered discrete  Intervals between elements are the same  Absolute zero exists  Theoretically numbers are infinite  Examples  Age  Length

Levels of Measurement Example of Ratio Data: Ruler  Continuous AND the intervals between the elements are the same

Levels of Measurement  Discrete  Continuous  Values can be ranked  Units between values have standard unit  Real Zero Levels of Measurement Ordinal Nominal Interval Ratio

LET’S SUMMARIZE WHAT WE HAVE LEARNED Levels of Measurement

Levels of Measurement Variables  Types  Discrete  Continuous  Levels of Measurement  Nominal  Ordinal  Interval  Ratio Acronym: NOIR

Levels of Measurement Test Yourself!  What are the following measures? After your guess, click and answer will appear Gender Age Apartment Number Attitudes on a Likert scale Temperature Opinion with a Likert scale

Levels of Measurement Test Yourself - Answers  What are the following measures? After your guess, click and answer will appear GenderNominal AgeRatio Apartment NumberNominal Attitudes on a Likert scaleOrdinal Temperature Interval Opinion with a Likert scaleOrdinal

Levels of Measurement Levels of Measures From lowest to highest sophistication:  Nominal - discrete  Ordinal – continuous, can be ranked, units between values vary  Interval – continuous, can be ranked, units between values standard, no real zero  Ratio – continuous, can be ranked, units between values standard, real zero Acronym: NOIR

Levels of Measurement Statistics  Analysis tools applied to measures bases on the level of measurement  Describe information and trends  Allow comparisons between sample groups and between a sample and its population Now you are ready to view the presentation: Basic Statistics & Levels of Measurement!

SCIENTIFIC RESEARCH PROCESS Levels of Measurement