DEV Community: Esther Karanja

Jumia Product Performance and Analysis.

Esther Karanja — Sun, 06 Sep 2026 00:14:28 +0000

Introduction

Jumia is one of Africa's leading e-commerce platform that manages millions of transcations with a diverse products from electronics,beauty products and many more categories.Therefore,tracking key perfomance indicators is essential for supply chain operatios and profit optimization.

Objective

My project aim is to build an interactive excel dashboard using Jumia transactional data.I aim to convert disorganized data into an interface that can help in decison making,identify trends and monitor products.

Dataset description

Data Cleaning and preparation process

Raw data mostly contains inconsistency and errors that may occur that may interfere or give the wrong output.

An example of a raw dataset

In the example above we can see inconsistent and missing data that we need clean in order to have an effective output.
First step is to format the prices from text to currency format and replace the before since excel will in order to calculate the discount eg below

The image above is the discount price which was obtained by finding the difference between the old price and the new price.

The image below is an example of the formula to categorize the prices whether high,low or medium.I used the IF,AND functions.
The difference when using the IF(AND function is that all the conditions must be met while in the IF(OR,only one condition has to be met.

In the image below i used IF and ANDfor the discount category.

In the image below i also used the IF AND functions in the ratings category.

After removing duplicates,removing inconsistent data eg texts in numbers columns.Below is an image of the cleaned version of the Jumia dataset.

An example of a clean dataset

Descriptive Analysis

To calculate the average current price of products i used the average formula and highlighted the cells eg =AVERAGE(B2:B113).The average old price of products was obtained by the same formula but now on the old price column =AVERAGE(D2:D113)

To calculate the number of product since they are in text format we will use =COUNTA(A2:A113)

To calculate the average product ratings we will use =AVERAGE(

We use the count function to calculate the total number of reviews.

We will use the MIN() and MAX()Formulas to calculate the least expensive product and most expensive product respectively.

Some of my pivot tables and charts include:

Slicers are interactive buttons to filter data used and to display the filters being applied.

Examples of slicers i will use are above.

Dashboard Analysis
My dashboard that had the following KPIs(KPIs translates and evaluates data for better understanding)

Key Insights
High discounts are not translating into higher customers satisfaction.

Poor rating dominates the donut chart at 60% while average accounts for 28% and excellent represents just 12%.eventhough the average rating is at 3.89 the volume of negative reviews show a potential of customers not being satisfied with the products.

The discount strategy seems to be leverage used to drive products interest to the customers.eg Over half of the catalogue falls under high discount while 32 products sits in medium discount range and only 19 products have low discounts.

My dashboard

Connecting slicers to multiple tables,charts and pivot tables

Conclusion

This case study has explored how ratings,reviews,prices and large discounts do not guarantee for major sales instead,for a platform like Jumia, consistent product quality and customers values are more important.
This is the link to this project on github(https://github.com/muthoni-ess/Jumia-Excel-Dashboard.git)

Getting Started with Excel for Data Analytics: From Basics to Data Cleaning.

Esther Karanja — Sat, 29 Aug 2026 11:41:27 +0000

Introduction

Excel is used in our day to day lives.
Excel is a microsoft spreadsheet used to store,organize and analyze data.
A row is horizontal that is from left to right while a column is vertical that is top to bottom.
A cell is an intersection of a row and a column.
Rows, columns and cells are contained in a worksheet.
One or more worksheets form a workbook

excel ribbon main components

Tabs-this are the headers on top ie File,Insert,Page layout,Formulas,Data,Review and view In each tab there are subsections,dropdowns theres also a dialougue launcher which is a small arrow at the bottom right corner that opens advanced settings panels.

A sample excel worksheet interface.

Common terms we may hear a lot:

Formatting this is just changing the visual appearance of data in a spreadsheet to make it easier to manipulate data and understand.
Sorting data this is basically arranging the text entries from A to Z or numerical values eg sales, arranging them form largest to smallest
Formulas all formulas start with the = sign to tell excel that the following is a calculation not a text.
Functions this are operations prebuilt in excel thet make calculations easy eg SUM,AVERAGE,VLOOKUP
Cell Referencing this shows the cells highligted or containing data eg A1,B2:B20)

What is Data Cleaning?

This is the process of removing inacurate,duplicate informations,blanks and any errors that may appear inorder for data analysis and reporting to be clear,accurate,seamless and easy'
Why is cleaning data important because we may experience some of the common issues like:

Duplicates-we basically get rid of duplicates by selecting all,clicking on the ribbon named data and removing duplicates or one could click on the column one wants to remove duplicates,under home ribbon,conditional formatting select remove duplicates or give conditions
Spelling errors-Select all,under review ribbon,spellings
Inconsistent spacing-use the TRIM command =TRIM()
Wrong formatting eg numbers formatted as text-select the column,under the home ribbon,select number format as required eg if its date,use the short date if its salary use accounting format,numbers under general etc or different date format,under the data ribbon,select text to columns and fill the date format you want to use eg DMY,YMD etc
Messy borders and blanks-to get rid of the blanks,ctrl G(go to shortcut) and click on special,type the replacement value,press ctrl enter it will replace blanks with the values i types eg 0,N/Aor Missing.
Text not standardized eg under name columns instead of Esther Karanja displays eStheR KaRanja.We use the formula =UPPER()will return ESTHER KARANJA uppercase.
We can use =LOWER()for all names to be in small case and =PROPER()for all the names in the normal case

After cleaning the data properly one can create a table ctrl T or under insert ribbon create table.

Conclusion

This week i have realized that cleaning data is a very important in the data analysis process and i should be keen and ensure everything is in the right format,no blanks,no redudant data,no spelling errors,spacing errors and many more errors that may be overlooked.

Understanding the Git Workflow:Working directory,staging ,commit and push.

Esther Karanja — Fri, 21 Aug 2026 22:22:18 +0000

Introduction

Understanding git has become easier for me when broken down into this four stages.
The working directory is where we write code,amend and delete files,here changes are made but can not be tracked unless they are instructed to commit.
The staging phase is an area where files are modified.
The commit phase is where git takes everything from the staging area and sends it to our local repository,
The push phase is where the saved commits are sent to a remote repository like github.

What is Git?

Git is a version control system or tool used to track changes by developers.
When one installs git it comes with an inbuilt terminal called gitbash

Understanding how Git works.

We start by installing git on my Pc, after installation is done one can check if git is installed by opening a terminal eg powershell on windows and run git --version

How to create folders and files on git bash

First identify where we want the folder to be located
lsis used to list
mkdir "name of the folder" (means make directory)cd " name of the folder"(change directory)

Readme texts README.mdend with .md since they are written using markdown language.Can use echo,touch or nano commands to write a readme file.
If i want to know the contents of my readme file we use:cat README.md

git config-this is basically telling it my identity
git config --user.name"Esther Karanja"
git config --user.email "my email"
git init-this command is used to create or initialize a repository in main/master.
git init main
git status-shows the repository status. This command shows changes and what is happening in git
git status
git add-stages changes made
git add .this means stage all or one can specify what to be added e.g i want to add only a javascript folder git add script.js
git commit-commits records that have been staged in the local git repository.Its like getting a snapshot or memory of the file.
git commit -m "write a commit message"
git log-shows a history of all the commits that were made.
git log

git branch should return main

To upload my git folder on github:
Open the github account,create a new repository,click on ssh and copy the link
git remote add origin "paste the ssh key link"

git remote -v

git push-this command to send commits to the remote repository git push -u origin main Git will send the files to my github repository,i can refresh my github and see them

What is github?

Github is a cloud based platform for storing git repositories online.
Just sign up for free,verify via email and your account is created.
git and github are connected using a SSH KEY.

What is a SSH KEY?

SSH stands for secure shell which is a protocol that allows a computer to communicate with another computer over a network.

So how do i generate an SSH key?
ssh-keygen -t ed25519 -C "email signed on github.com"and press enter, the passphase(password authentication)is optional.
This command will generate two keys:example
ed25519
ed25519.pub
The one with .pub is the public key which is the one that we share with github while the other one is a private key which should not be shared.

How to add the SSH Key to Github-open my github account,on settings click on SSH and GPG keys, create a new key and copy the public key that we generated.
How to test the SSH connection
Test before pushing a project using ssh -T git@github.com

In conclusion,i can say that using git and github is easier than i thought,the commands are self explanatory.Basically,i just create my project locally,initialize git,connect my github account and git together using the SSH keys, create a repository,commit and push them to my github account