Understanding the Difference Between Sample and Population
 Overview
 Populations are hard to observe
 Samples are less time consuming and less costly
 Lets assume we walk to university canteen to collect the details from students who will be the sample
 Sample has to have two important characteristics
 Randomness
 Representativeness
 Students from canteen violate both randomness and representativeness.
 In this case how to draw a sample that is both random and representative, for this we need to have an access to university student database and then we choose sample out of it which are random & reprsentative.
10000 feet overview of descriptive and inferential statistics

Descriptive Statistics
 75% of the website traffic on flipkart.com is interested in mobiles
 (We have some data & we conducted statistics on that => concluded)

Inferential Statistics
 According to survey which we conducted the average rent in hyderabad for 2 BHK will be 20000 by 2025
 (This study has taken a sample and predicted the observation for the whole population)
Descriptive Statistics Fundamentals
 When we deal with statistics we deal with data
 Data is classified by
 Types of Data
 Categorical:
 This represents groups or categories
 Examples: Car Brands (BMW, Audi, Mercedes), Answer to yes/no questions
 Numerical: This represents numbers and is divided into two categories
 Discrete:
 This generally represent the data that can be usually counted in a finite matter
 Example: Number of cars, SAT score
 Continuous:
 This generally represents data which is not possible to count which we rather measure
 Example: Weight, height
 Discrete:
 Categorical:
 Measurement Levels
 Qualitative
 Nominal:
 Represents categories that cannot be put in any order
 Examples: Four seasons, Car brands
 Ordinal:
 Represents categories that cna be ordered
 Example: rating your meal (disgusting, unappetizing, neutral, tasty and delicious)
 Nominal:
 Quantitative: Both represent numbers
 intervals:
 dont have true zeros
 Example: Degrees celsius and Fahrenheit
 ratios:
 Have true zero’s
 Example: lenght, degrees kelvin
 intervals:
 Qualitative
 Types of Data