4.1 Descriptive Statistics Lesson 01

This lesson is a kind of review.

4.1.1 What is data?

Data could be whatever thing: Text, Spreadsheets, video, images, database, etc.

4.1.2 Data types

• Quantitative Data: Allow us to perform mathematical operations with data (1, 2, 3, 4, etc.);
  • Continuous: Could be any real number (Age);
  • Discrete: Only integer number (Number of persons);
• Categorical Data: Used to label a group or a set of items (blue, yellow, red, etc.);
  • Ordinal: There are a way to put the categories in a scale (Very good, so-so, very poor);
  • Nominal: It is impossible to put the categories in order (blue, yellow, orange, etc.);

4.1.3 Measures of Center

4.1.3.1 Categorical

The categorical data is analyzed doing a simple summary to count the total of each category has.

4.1.3.2 Quantitative

Four main aspects when analysing quantitative data:

• Measures of Center
  • Mean
  • Median: The median splits our data so that 50% of our values are lower and 50% are higher.
    • Even number of elements: single values.
    • Odd number of elements: average between two “center” values.
  • Mode: The mode is the most frequently observed value in our dataset.
    • No mode: If all observations in our dataset are observed with the same frequency, there is no mode.
    • Many modes: If two (or more) numbers share the maximum value, then there is more than one mode.
• Measures of Spread
• The Shape of the Data
• Outliers

 

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A work by AH Uyekita

anderson.uyekita[at]gmail.com