Quartiles for even and odd length data set in data mining

By: Prof. Dr. Fazal Rehman | Last updated: December 26, 2023

What is quartile?

Quartile means four equal groups. 

How to find quartiles of odd length data set?

Example:
Data = 8, 5, 2, 4, 8, 9, 5
Step 1: First of all, arrange the values in order. After ordering the values:
Data = 2, 4, 5, 5, 8, 8, 9
  Step 2: For dividing this data into four equal parts, we needed three quartiles. Q1: Lower quartile Q2: Median of the data set Q3: Upper quartile Step 3: Find the median of the data set and label it as Q2.
Data = 2, 4, 5, 5, 8, 8, 9 Q1: 4 – Lower quartile Q2: 5 – Middle quartile Q3: 8 – Upper quartile Inter Quartile Range= Q3 – Q1                                   = 84                                   = 4  What is Outlier? The outlier is the set of data far away from the common and famous pattern.

How to find outliers?

Outlier is mostly a value higher or lower than 1.5 * IQR =1.5 * IQR =1.5 * 5 = 7.5 Population size: Population size is the total number of values in data.
 
 

How to find quartiles of even length data set?

Example:
Data = 8, 5, 2, 4, 8, 9, 5,7
Step 1: First of all, arrange the values in order After ordering the values:
Data = 2, 4, 5, 5, 7, 8, 8, 9
Step 2: For dividing this data into four equal parts, we needed three quartiles. Q1: Lower quartile Q2: Median of the data set Q3: Upper quartile Step 3: Find the median of the data set and label it as Q2.
Data = 2, 4,   ♦    5, 5,     ♦    7, 8    ♦    8, 9 Minimum: 2 Q1:  4 + 5 / 2 = 4.5    Lower quartile Q2:  5+ 7 / 2 = 6        Middle quartile Q3:  8 + 8 / 2 = 8       Upper quartile Maximum: 9 Inter Quartile Range= Q3 – Q1 = 8 –  4.5 = 3.5 Outlier is mostly a value higher or lower than 1.5 * IQR =1.5 * IQR =1.5 * 3.5 = 5.25

Next Tutorials with Similar Topics

  1. Type of Data that can be mined – Click Here
  2. Attributes Types – Click Here
  3. Mean, Median, Mode – Click Here
  4. Estimated Mean, Median, Mode – Click Here
  5. Data Quartiles – Click Here
  6. Box Plot for Data – Click Here
  7. Variance and standard deviation of data in data mining – Click Here   Calculator –  Click Here

  8. Data skewness – Click Here
  9. Correlation analysis of numerical data in Data Mining – Click Here
  10. Correlation analysis of Nominal data with Chi-Square Test in Data Mining – Click Here
  11. Data discretization and its techniques in data mining – Click Here

Leave a Comment

All Copyrights Reserved 2025 Reserved by T4Tutorials