Module 3: Dealing with Different Type of Data

What is an observation in data analytics?

A single row or record of data containing measurements for a unit of analysis.

What are other terms for an observation?

Case, record, pattern, or row.

What is a variable in a dataset?

An attribute or characteristic measured for each observation.

What is data sampling?

A statistical technique for selecting, manipulating, and analyzing a representative subset of data points.

What is the purpose of data sampling?

To identify patterns and trends in a larger dataset using a representative sample.

What is sample size?

The number of observations included in a sample, commonly represented by n.

What are the advantages of data sampling?

It is cost-effective, reduces the amount of data to examine, and supports findings about a larger population when the sample is appropriate.

What is a dataset?

A collection of data captured for a particular use case.

What types of content can a dataset contain?

Numbers, text, images, videos, and other forms of information.

What is prediction in data analytics?

The process of using available information to provide an assessment of what is likely to happen.

What are the three main types of data based on structure?

Structured data, unstructured data, and semi-structured data.

What is structured data?

Data organized and stored in a fixed format.

What is unstructured data?

Data that lacks a predefined, fixed structure.

What is semi-structured data?

Data that combines structured elements with information that does not follow a rigid tabular structure.

What is an example of structured data?

Employee details, job positions, and salaries organized in a table.

What is an example of unstructured data?

An email.

What are examples of semi-structured data?

CSV and JSON documents, as presented in the lesson.

What is unstructured data commonly used for in business analytics?

Business intelligence and analytics rather than transaction-processing applications.

How can retailers and manufacturers analyze unstructured data?

For sentiment analysis of product reviews, targeted marketing, and improving customer relationship management.

What are qualitative data?

Data that classify objects according to attributes or properties rather than numerical measurements.

What are quantitative data?

Data that can be measured and expressed numerically.

What question does qualitative data commonly help answer?

Why?

What questions do quantitative data commonly help answer?

How much? or How many?

What is the main purpose of qualitative data collection?

To develop an initial understanding and help define a problem.

What is the main purpose of quantitative data collection in the lesson?

To analyze numerical information and help recommend a course of action.

What are the two subgroups of qualitative data?

Nominal data and ordinal data.

What is nominal data?

Categorical data whose categories have no inherent order.

What is ordinal data?

Categorical data whose categories have a meaningful order or ranking.

What is the key difference between nominal and ordinal data?

Nominal data classifies without a meaningful order; ordinal data classifies with a meaningful order.

What are the two subgroups of quantitative data?

Discrete data and continuous data.

What is discrete data?

Numerical data that can take only certain distinct values.

What is continuous data?

Numerical data that can take any value within a specified range.

What is the key difference between discrete and continuous data?

Discrete data takes distinct countable values; continuous data can take any value within a range.

What are the four levels of measurement?

Nominal, ordinal, interval, and ratio.

What is a level of measurement?

A classification describing the nature of information represented by values assigned to variables.

What does the nominal level of measurement indicate?

Categories used to classify data without indicating order.

What does the ordinal level of measurement indicate?

Categories or measurements arranged in a meaningful order.

What does the interval level of measurement indicate?

Measurements that can be classified and ordered, with equal distances between values.

What does the ratio level of measurement indicate?

Measurements with ordered values, equal intervals, and a meaningful zero.

What is the key difference between interval and ratio measurements?

Ratio data has a meaningful zero; interval data does not have a true zero representing the complete absence of the measured quantity.

What is the correct order of the four measurement levels from simplest to most informative?

Nominal, ordinal, interval, ratio.

What is the normal distribution?

A continuous, symmetric, bell-shaped probability distribution also known as the Gaussian distribution.

What are the main characteristics of a normal distribution?

It is symmetric and bell-shaped, has one peak, is densest around the center, and has equal mean, median, and mode.

What is the relationship among the mean, median, and mode in a normal distribution?

They are equal.

What does it mean that the tails of a normal distribution are asymptotic?

The tails approach the horizontal axis but do not reach it.

What are the three basic statistical parameters discussed in the lesson?

Mean, variance, and standard deviation.

What is the mean?

The arithmetic average, calculated by dividing the sum of all data values by the number of values.

What is the formula for the mean?

Mean = sum of all data values ÷ number of data values.

What is variance?

A measure of how data values are spread around the mean, calculated using squared differences from the mean.

What is the population variance formula used in the lesson?

Variance = sum of squared differences from the mean ÷ number of data points.

What is standard deviation?

The square root of variance, indicating how much data values vary around the mean.

What is the formula for standard deviation?

Standard deviation = square root of variance.

How are variance and standard deviation related?

Standard deviation is the square root of variance.

What does a smaller standard deviation generally indicate?

Data values are more tightly clustered around the mean.

What does a larger standard deviation generally indicate?

Data values are more spread out around the mean.

What are the three types of data based on structure?

Structured, unstructured, and semi-structured data.

What are the four levels of measurement?

Nominal, ordinal, interval, and ratio.

What are the basic statistical parameters covered in the lesson?

Mean, variance, and standard deviation.