Lecture 1.2 - Introduction and Types of Data - Understanding data

Question 1

What is Data?

Answer 1

1. Data collection is necessary to learn something.
2. Data are facts and figures that are collected, analyzed, and summarized for presentation and interpretation.
3. Statistics relies on data, information that surrounds us.

Question 2

Why do we collect Data

Answer 2

1. Interested in characteristics of people, places, things, or events.
2. Example: Interested in temperatures in Chennai in a particular month.
3. Example: Interested in marks obtained by students in Class 12.
4. Interested in how many people like a new song, product, or video, collected through comments.

Question 3

Data Collection

Answer 3

1. Data available: Published data.
2. Data not available: Need to collect or generate data.
3. Statistical analysis is done on available data, assuming it’s already available.

Question 4

Unstructured and structured data

Answer 4

1. Context of the numbers and text in a database must be known to make it useful.
2. Scattered and unstructured information is of very little use.
3. Organizing data is necessary; structured data is a collection of values, such as numbers, names, and roll numbers.

Question 5

Variables and cases

Answer 5

1. Case (observation): A unit from which data are collected.
2. Variable: A characteristic or attribute that varies across all units.
3. In a school data set, each student is a case and variables include name, marks obtained, board, etc.
4. Rows represent cases: For each case, the same attributes are recorded.
5. Columns represent variables: For each variable, the same type of value from each case is recorded.