AMS 5 Lecture Notes - Lecture 3: Polio Vaccine, Categorical Variable, Walnut Creek, California

• School: UCSC
• Department: Applied Math and Statistics
• Course: AMS 5
• Professor: Yonatan Katznelson

Document Summary

Each observation yields values for one or more variables. Quantitative variables can be discrete or continuous: discrete variables can take values that differ by fixed amounts, usually used to count things. E. g. , number of children (for smaller integers): continuous variables can take values that differ by arbitrarily small amounts. E. g. , height, temperature, and usually money (non-integer numbers). Interval variables the difference between two values has a reasonable interpretation, but the ratio does not. E. g. , temperature (ex: today"s temperature is 60, tomorrow"s is. 55; you wouldn"t say tomorrow"s temp was 11/12th of what it was the day before). Ratio variables the ratio between two values has a reasonable interpretation. E. g. , height. (someone who is twice as tall as someone else) Usually if you can go negative in your data (like temp), it"s not a ratio variable. Example: 500 households are surveyed by a marketing research firm.