DEV Community

Rajasekaran Palraj
Rajasekaran Palraj

Posted on

Data Analytics Week 1 Notes

Data Analytics

It is a process of examining, cleaning, transforming and interpreting data to discover useful information, draw conclusions and support decision-making. It helps businesses and organizations understand their data better, identify patterns, solve problems and improve overall performance.

**
How data analytics works:**

  • Define Objectives
  • Data Collection
  • Data Cleaning & Data Processing
  • Analysis Techniques
  • Interpretation of Results
  • Visualization and Communication

Technical Skill for Data Analytics

  • SQL
  • Statistics
  • Excel
  • Data Visualization
  • Programming Languages
  • Mathematics

Data 

**What is data?**
Enter fullscreen mode Exit fullscreen mode

Data is distinct pieces of information, usually formatted in a special way

**
Data can be generated by:**
Humans
Machines
Human-Machine combines.

Why data is so important?

  • Data helps in making better decisions.
  • Data helps in solving problems by finding the reason for underperformance.
  • Data helps one to evaluate performance.
  • Data helps one improve processes.
  • Data helps one understand consumers and the market.

Categories of Data
Data can be categorized into two main parts -

  • Structured data
  • Unstructured data

Excel

Ribbon: The toolbar at the top of Excel which is divided into tabs that group related tools and commands.
Formula Bar: Displays the contents or formulas of the active cell and allows editing.
Worksheet Area: The grid where we enter and manipulate our data and it is made up of rows and columns.
Navigation Tools: It includes sheet tabs at the bottom, scroll bars and zoom controls for easy movement within our workbook
All Tabs in Excel Ribbon
Ribbon is divided into several tabs and each serving different purposes:
Home Tab: The most commonly used tab for everyday tasks. It includes formatting options (font, alignment, colors), number formatting, table styles, cell editing and basic tools like AutoSum and Sort & Filter.
Insert Tab: Lets us add tables, charts, images, shapes, hyperlinks, text boxes, symbols and sparklines to make our worksheet more visual and interactive.
Page Layout Tab: Controls how our worksheet looks when printed. Adjust themes, margins, page orientation, size, print area and background here.
Formulas Tab: The central place to create and manage formulas it includes the Function Library for logical, text, date, math and financial functions, plus named ranges and formula auditing tools.
Data Tab: Helps us import, organize and analyze data. Key features include Get & Transform (Power Query), Sort & Filter, Data Validation, Flash Fill, Text to Columns and Forecast tools.

Formulas:
=SUM(Arg1: Arg2): It is used to find the sum of all the numeric data specified in the given range of numbers.
=COUNT(Arg1: Arg2): It is used to count all the number of cells(it will count only number) specified in the given range of numbers.
=MAX(Arg1: Arg2): It is used to find the maximum number from the given range of numbers.
=MIN(Arg1: Arg2): It is used to find the minimum number from the given range of numbers.
=TODAY(): It is used to find today's date.
=SQRT(Arg1): It is used to find the square root of the specified cell.

What is Workbook?
A collection of worksheets is referred to as a workbook (spreadsheets). Workbooks are your Excel files. You'll need to create a new workbook every time you start a new project in Excel. There are various ways to begin working with an Excel workbook. You can either start from scratch or use a pre-designed template to create a new workbook or access an existing one.

Characteristics of a good worksheet
An appealing worksheet should have specific titles that indicate what it is about as well as pictures or other clipart to draw some attention.
It is important that the paper and the writing are in good contrast so that eye strain is minimized.
Users should be able to do the worksheet independently by following the directions with examples.
Despite the fact that the worksheet needs to illuminate a pattern in problem solving or usage, it shouldn't grind an idea into dust.
Once the worksheet has been completed, the user should be able to explain how it was formed or what it was meant to teach: the answer to this question should be linked to the worksheet's title.

Important functions

  • Create table (Home > Style > Format Table)
  • Count Nulls (select columns then =COUNTBLANK())
  • sorting( Select Data > Data Tab> Sort)

  • Filter

    • Data between Filter
    • Number greater than or equals filter
    • Clear Filter

  • Total Row function

  • Conditional Formatting

    • Select Range
    • Choose Formatting
    • Data Bars
    • Color Scales
    • Manage Rule
    • Top/Bottom Rules

  • If Function

  • SumIf/SumIfs

    • Range
    • Criteria
    • Sum Range

  • AvergeIf/AverageIfs

Chart Types

Understanding Your Data and Visualization Goals
Before choosing the right chart it's essential to understand the nature of your data and the message you want to convey. To understand consider the following questions:

  • What is the primary purpose of the visualization?
  • What type of data are you working with?
  • How many variables are you visualizing?
  • What is the volume of data points?

1. Comparison Charts

  • Bar Chart: Compares categories using horizontal bars (e.g., product sales).
  • Column Chart: Uses vertical bars, great for time-based or hierarchical data.
  • Radar Chart: Displays multiple variables in a circular layout, ideal for comparing performance across categories

2. Trend Charts

  • Line Chart: Shows trends over time with connected points (e.g., monthly sales).
  • Area Chart: Like a line chart but fills the space below, showing cumulative totals.
  • Waterfall Chart: Displays how increases and decreases affect a total (e.g., profit changes).

3. Relationship Charts

  • Scatter Chart: Plots two variables to show their relationship or trend.
  • Bubble Chart: Adds size and color to scatter plots for more variable comparison.
  • Heatmap: Uses color in grids to reveal patterns, density or relationships in data.

4. Distribution Charts

  • Histogram: Shows frequency of values within ranges.
  • Box Plot: Displays data spread, median and outliers.
  • KDE Plot: Smooth curve showing data distribution shape.
  • Violin Plot: Combines box plot and density curve to compare group distributions

5. Composition Charts

  • Pie Chart: Best for small datasets shows each part’s share of the total.
  • Stacked Bar Chart: Compares parts across categories within bars.
  • Treemap: Uses nested boxes sized by value to show part-to-whole relationships.

6. Geographical Charts

  • Choropleth Map: Uses color to show values (like population or income) across regions.
  • Cartogram: Resizes regions based on data values (e.g., population) distorting geography for emphasis.ed

Top comments (0)