Lecture 1 Flashcards
Data Types and Statistics Definitions
What are descriptive statistics?
Measures of central tendency and measures of dispersion. Simply describes the data
Measures of central tendency
Mean, Median and Mode
Measures of dispersion
Range, Standard deviation, Variance and Absolute Deviation
What are inferential statistics?
Hypothesis Testing and Regression Analysis. Used to see if trends in sample data are a true representation of trends in the population
Hypothesis Testing
Z-Test, T-Test and F-Test
Regression Analysis
Linear Regression
Population
All the individual items that could be studied.
Sample
A selection of items from the population
Data collected from subjects is called…
Observations
Individual items in a sample
Subjects/ Sample Units/ Cases
Differences between subjects are….
Variables (maybe fields)
Data
Numerical information that we use to extract and interpret meaning
Quantitative Data
Information has a directly measurable (numerical) value. E.g. height, weight, age
Qualitative Data
Information that is non-numerical and most often descriptive. E.g. good or bad. Often categorical
Categorical Data
Data fits into named categories with no in-between. E.g. Blood type. Includes nominal data and ordinal data
Nominal Data
No ordering to the categories. E.g. Alive vs Dead, Political Affiliation, Species of Snail. Discrete
Ordinal Data
Has an ordering to the data. E.g. sporting scores and fixture. IMPORTANT: these orderings are not mathematically linked. E.g. the winners of the world cup are not twice as much the “winners” as the runners up. Used for comparisons
Quantitative Data Types
Discrete Data and Continuous Data
Discrete Data
Can only take certain values. E.g. when counting the number of people, we cannot have half a person
Continuous Data
Can take any value within a given range. E.g. height, weight, blood pressure
Continuous Data Types
Interval and Ratio
Interval
Can take any value within a given range, but a value of zero does not indicate an absolute zero
Ratio
Can take any variable within a range. The value doesn’t need to be a whole number but the zero must be a true zero. E.g. height of a house. Continuous
Is Temperature an Interval or Ratio Variable?
Interval - 0ºC is not true zero. Note: 100ºC is not twice the temperature of 50ºC
Levels of Measurement
Nominal, Ordinal, Interval and Ratio
Can Qualitative Data be converted to Quantitative Data for Analysis?
Yes. E.g. Pain scale, happiness meter