Quantitative method intro variable_levels_measurement
- 1. Quantitative Methods Variables and the three levels of measurement 変数と計測レベル 2016 Keiko Ono, Ph.D.
- 2. More Key Terms in Quantitative Methods • Unit of Analysis 分析単位 • Observations, cases, records (in rows) 観察・観測対象 となるもの • Variables (in columns) 変数 – Values – Levels of measurement • Measures of association – Chi square χ2 カイ2乗 – Compare means test T検定 – Correlation 相関関係
- 3. A variable: an empirical property of an observation that can take on two or more different values.
- 4. Remember the “favorite color” data set? There are 59 cases/observations in total. What do they represent? In other words, what is the unit of analysis? How many “empirical properties” (variables) are recorded for the observations?
- 5. A variable must vary (by definition). The gender variable could take one of the two values: girl or boy. The favorite color variable could take one of several values: pink, blue, white, yellow, white…etc. The age variable could take one of several values: 17-24.
- 6. Three levels of measurement for variables • Nominal (or “Categorical”) Values communicate differences b/w subjects on the characteristic being measured. Variable “color”: each value (pink, white, blue…) represents a different category of color. Cannot be ordered. • Ordinal Values communicate relative differences b/w subjects on the characteristic being measured. Can be ordered. -ordered ranking -ordered categories (cloudy---partly cloudy---sunny) • Interval (or “Scale”) Values communicate exact differences b/w subjects on the measured characteristics. Variable “age” : each value (17, 18, 19…) represents the student’s age in years. Can be ordered.
- 7. Three levels of measurement for variables in the Color dataset • Nominal (or “Categorical”) Variable “color”: pink, white. Variable “gender”: boy, girl. • Ordinal • Interval (or “Scale”) Variable “age” : each value (17, 18, 19…)
- 9. Men’s individual 400m medley
- 10. Men’s individual 400m medleyOrdinal Nominal Interval
- 11. Yet another sport example. Yomiuri (巨人) and Soft Bank (ソフトバンク) both came in second (2位）。 But were they equally successful in winning games? http://baseball.yahoo.co.jp/npb/standings/
- 12. Summary Statistics and Levels of Measurement Categorical (or “nominal”) Ordinal Interval (or “scale”) Frequency ☺ ☺ ☺ Mode ☺ ☺ ☺ Mean X X ☺ Median X ☺ ☺ Variance and σ X X ☺ Minimum X ☺ ☺ Maximum X ☺ ☺ Range X X ☺