# Tools of Data Science (G7, W7, M7)

I arranged G7, W7 and M7 as basic tools of Data Science . The original idea of these tools is from " Seven QC Tools and New Seven QC Tools " (Q7 and N7).

G7 and W7 are for beginners. M7 is for middle class users.

## G7

"G" of G7 is "Graphs of Numbers". G7 is similar to Q7 .

Stratified Sampling is also useful in G7

• Bar Graph : Analysis of size. ("Pareto Chart" is arranged bar garaph.)
• Line Chart : Time series analysis. ("Control Chart" is one of the line chart.)
• Circle Graph : Analysis of ratio
• Histogram : Analysis of distribution of 1 variable. (One of the Bar Graph)
• Box Plot : Analysis of distribution of 1 variable. (similar to stratified histogram)
• Scatter Diagram : Analysis of the relationship of two variables. Analysis of distribution of composed 2 variables. (To find outlier or to study small data set)
• Heat Map : Analysis of the relationship of two variables. Analysis of distribution of composed 2 variables. (To study big data set)

## W7

"W" of W7 is "Analysis of Words". Most of W7 are Concept Analysis .

• Affinity Diagram : Classification of idea. The method to collect Brainstorming
• Cause-and-Effect Diagram : To collect reasons and results.
• Tree Diagram : Similar to FMEA . The next step of Cause-and-Effect Diagram.
• Relation Diagram : Main part of Systems Thinking .
• Matrix Diagram : Applications are QFD , Multi Dimensional Scaling and AHP.
• PERT : Planning method.
• Flow Chart : Analysis of the process

Why-why Analysis is a basis of concept analysis

W7 analyze the struture of phenomena as levels or networks. The idea to think the structure is also useful in G7 and M7.

## M7

"M" of M7 is "Mathematical Analysis".

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