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

Analytics progresses from descriptive (summarizing past data), to diagnostic (identifying causes), to predictive (forecasting future outcomes), to prescriptive (recommending actions), each building on the previous level.

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

Structured data fits neatly into relational databases with defined schemas (spreadsheets, SQL databases). Unstructured data lacks a predefined format (emails, social media posts, images, videos) and requires different processing approaches.

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

A p-value represents the probability of observing results as extreme as or more extreme than the data, given that the null hypothesis is true. A p-value below a chosen threshold (typically 0.05) leads to rejecting the null hypothesis.

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

ETL is the process of extracting data from various sources, transforming it (cleaning, standardizing, aggregating), and loading it into a target data warehouse or analytics platform for analysis.

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

Correlation indicates two variables move together (positive or negative relationship), but causation requires proof that one variable directly influences the other. Confounding variables can create spurious correlations.

Data Analytics Certifications (DAC) Practice Test

Data Analytics Certifications (DAC) Practice Test

DAC Data Analysis Fundamentals