DAC Data Analysis Fundamentals

Question 1

What are the four types of data analytics?

Accepted Answer

Descriptive (what happened), diagnostic (why), predictive (what will happen), and prescriptive (what should we do)

Answer

Only descriptive and predictive

Answer

Qualitative and quantitative only

Answer

Input, process, output, and feedback

Question 2

What is the difference between structured and unstructured data?

Accepted Answer

Structured data is organized in rows/columns (databases); unstructured lacks predefined format (text, images, video)

Answer

All data is structured

Answer

Unstructured data cannot be analyzed

Answer

They are the same thing

Question 3

What is a p-value in statistical hypothesis testing?

Accepted Answer

The probability of obtaining results at least as extreme as observed, assuming the null hypothesis is true

Answer

The percentage of data that is correct

Answer

The power of a statistical test

Answer

The precision of a measurement

Question 4

What is ETL in data analytics?

Accepted Answer

Extract, Transform, Load — the process of moving data from sources, cleaning/transforming it, and loading into a data warehouse

Answer

A programming language for data analysis

Answer

An encryption technique for data security

Answer

A type of data visualization

Question 5

What is the difference between correlation and causation?

Accepted Answer

Correlation measures the statistical relationship between variables; causation means one variable directly causes changes in another

Answer

They always mean the same thing

Answer

Causation is weaker than correlation

Answer

Correlation always implies causation

Question 6

What is data cleaning and why is it important?

Accepted Answer

Identifying and correcting errors, inconsistencies, and missing values in datasets; critical because analysis quality depends on data quality

Answer

Deleting all data and starting over

Answer

Only removing duplicate records

Answer

A cosmetic process that doesn't affect analysis