180DC NSUT presents
MASTERCLASS 2.0
Spreadsheets of the Uncertains
An Ice-Breaker
Which political
party will win UP
Elections 2022?
Comment Now!
The Problem
How many momos plate
sold in Delhi ?
How many maggies are
sold in a week ?
Any Guesses?
BUT WHAT IS A
GUESSTIMATE?
UNDERSTANDING WHAT GUESSTIMATE MEANS
GUESSTIMATE = GUESS + ESTIMATE
It is an estimate made without using adequate or
complete information, or in other words, an
estimate arrived at by guesswork or conjecture.
A guesstimate may be the first rough
approximation awaiting a more accurate estimate,
or it may be an educated guess at something for
which no better information will become available.
WHERE CAN IT BE USED
PHYSICS
Widely use of
guesstimation
techniques to solve
Fermi problems is
taught as a useful skill
to science students.
ECONOMICS
ENGINEERING
Economic
forecasts and
statistics are often
based on
guesstimates.
New development
of features and
release timelines
are based on effort
guesstimates of
tasks.
ASTRONOMY
The Drake
equation is a wellknown
guesstimation
method.
THE FLOW TO SOLVE A GUESSTIMATE
Make all the genuine
Assumptions and Facts
S
T
A
R
T Clarifications about
the question
Estimate each short problem
using math and assumptions
Break down the problem
into smaller problems
Consolidate the
smaller problems to
get the final result
F
I
N
I
S
H
LET’S TAKE AN EXAMPLE
HOW MANY PLATES OF MOMOS ARE
SOLD IN DELHI IN A SINGLE DAY?
ESTIMATE NUMBER OF PLATES OF MOMOS SOLD DAILY
CLARIFICATIONS BEFORE STARTING
Age group of customers Youngsters, 12-30
STATING THE FACTS
Population of Delhi ~30 million
Ratio of youngsters
~50%
ESTIMATE NUMBER OF PLATES OF MOMOS SOLD DAILY
MAKING THE ASSUMPTIONS
10% of youngsters prefer eating momos
Average person consumes 2 plates in a
week i.e. 0.3 plates daily
CONSOLIDATE AND CALCULATE!
Acknowledging specific cases
Combining all the factors and
percentages to calculate the estimated
number
APPLE CASE STUDY
HOW MANY APPLE PRODUCTS ARE SOLD NATIONWIDE IN
A SINGLE YEAR?
ESTIMATE NUMBER OF APPLE PRODUCTS SOLD YEARLY
Are we considering
internal tradeoffs and
second-hand sales? No.
What type of customers are
we considering? Everyone
who holds wealth and can
afford.
The lifespan of an
average product - 5 years
Family distribution - 4
persons per household
Products we are considering:
iPhone, MacBook, iPad,
Apple Watch
LET’S START SOLVING - FACTS AND ASSUMPTIONS
~1.3 billion population
ASSUMPTIONS : ULTRA RICH
50% of all ultra-rich population
use an apple product
50%
Average 6 products in one
household
CALCULATIONS : ULTRA RICH
Total ultra rich population is 5% of total Indian population = 65mn
Assuming 50% of them prefer apple products = 32.5mn
Total families = 32.5mn/4 = 8mn families
Assuming each family owns 6 products, total products = 8mn x 6 = 48mn products
If lifespan is 5 years for a single product
Product sold = 48mn/5 years = 9.6mn products/year
ASSUMPTIONS : RICH
25% of all rich population use an
apple product
25%
Average 2 products in one
household
CALCULATIONS : RICH
Total rich population is 15% of total Indian population = 195mn
Assuming 25% of them prefer apple products = 48.75mn
Total families = 48.75mn/4 = 12.18mn families
Assuming each family owns 2 products, total products = 12.18mn x 2 = 24.3mn products
If lifespan is 5 years for a single product,
Product sold = 24.3mn/5 years = 4.8mn products/year
ASSUMPTIONS : MIDDLE CLASS
5% of all middle-class population
use an apple product
5%
Average 1 products in one
household
CALCULATIONS : MIDDLE CLASS
Total middle class population is 40% of total Indian population = 520mn
Assuming 5% of them prefer apple products = 26mn
Total families = 26mn/4 = 6.5mn families
Assuming each family owns 1 products, total products = 6.5mn x 1 = 6.5mn products
If lifespan is 5 years for a single product
Product sold = 6.5mn/5 years = 1.3 mn products
ASSUMPTIONS : POOR
0% of all poor population use an
apple product
Average 0 products in one
household
0%
Total products is also
0
SUM TOTAL
9.6mn + 4.8mn + 1.3mn ~15mn products
sold in a single financial year!
BREAKING DOWN INTO SOLUTION TREE
THANK YOU FOR SHOWING UP!