DSDA 01 Basic Terms

Basics terms of Data Analysis

• Raw Data: Uncleaned version of data collected from different sources

• Variable: Hold different values

  • Categorical variable: Places an individual or an item into are of several groups or categories. (Ordinal variable is when categories have an ordering or ranking)
  • Quantitative variable: Takes numerical values for which arithmetic operations such as adding and averaging make sense. (measurement variable)

  ex)

  1. Age: numerical
  2. Typical classroom seat location(front/middle/back): categorical
  3. Number of songs on an ipad: numerical
  4. time spent studying(in hours): numerical

Summerizing Data

• mean: Average value

• median: Middle value of the data is arranged from the smallest to the largest

• Range: Measures the spread over 100% of data. (Range = High value - low value = Max - min)

• Persentiles: The Pth percentile is the value that P% of observations fall at or below that value
  Q1: 25th percentile(first quartie)
  Q2: 50th percentile(median)
  Q3: 75th percentile(third quartie)
  Interquatie range: P3-Q1

  ex)
  ordered: 63, 65, 67, 69, 69, 71, 71, 72, 74, 75, 78, 79, 80, 81, 83

  mean: 73.13 (1097/15)
  median: 72
  Q1: 69
  Q3: 79
  Variance: 37.12
  STD: 5.89

• std-deviation:
  

• variance