Data Analytics & Data Warehousing Reviewer (Quizzes 1–5)

Flashcards covering core concepts, terminology, and practice quiz solutions for Data Analytics, ETL, Data Warehousing, OLAP/OLTP, Data Modeling, and Power Query.

Why is an online marketplace collecting searches, clicks, orders, payments, reviews, and delivery updates considered Big Data?

It is large, fast, diverse, and complex

Which Big Data characteristic is mainly being addressed when a ride-hailing company receives live GPS coordinates every few seconds?

Velocity

Which type of analytics is applied when estimating which subscribers are likely to stop using a service next month?

Predictive

What question does a public-health dashboard reporting dengue cases recorded in each province during the past month primarily answer?

What happened?

What is the typical output when using previous consumption and weather patterns to estimate electricity demand next week?

Forecasts and probabilities

Which combination best describes the key challenge and application when monitoring digital-wallet transactions and flagging unusual activity within seconds?

Velocity and fraud detection

Which Big Data characteristic is the main concern when discovering duplicate student records, missing grades, and inconsistent date formats?

Veracity

Which Big Data characteristic best describes combining patient tables, doctors' notes, X-ray images, and audio recordings for analysis?

Variety

Which type of analytics produces the recommendation when forecasting passengers and suggesting how many buses to deploy on each route?

Prescriptive

Which Big Data characteristic is most evident when storing five years of high-definition video from hundreds of road cameras?

Volume

Which question is answered when selecting the best warehouse for delivery based on predicted orders, distance, and capacity limits?

What should we do?

Which response is accurate if a dataset has high inconsistency but lacks extreme volume?

Different projects can face different V-related challenges

What requirement follows when a small company tries to process continuously growing sensor data with a traditional spreadsheet, but updates become too slow?

Scalable storage and processing

What is the expected output when comparing system logs with server outage times to determine the cause of a website traffic drop?

Causes and relationships

Which Big Data characteristic is achieved when weather and crop-sensor data improve irrigation decisions?

Value

Which type of analytics is used to find the reason why sales fell in June by examining stock records?

Diagnostic

Which sequence of analytics is used when predicting heavy demand next weekend and then choosing staffing levels under budget limits?

Predictive then prescriptive

What process is performed when combining enrollment records, grades, attendance logs, and LMS activity into one dataset?

Data integration

Which integration challenge must be solved when a customer appears under slightly different names across different systems?

Identity matching

What structure does a dataset use when storing student numbers, program names, and grades in rows and columns with fixed data types?

Structured

Which ETL stage occurs when retrieving booking records from Excel files, a reservation database, and an online API?

Extract

Which challenge is evident when hourly sales data is combined with weekly supplier updates, causing inconsistent totals?

Data latency because sources update at different times

Which ETL stage occurs when converting ticket prices to one currency, standardizing airport codes, and removing duplicate bookings?

Transform

Why are JSON order records with optional or nested fields classified as semi-structured data?

Semi-structured because keys organize records without a rigid table schema

Which data category and methods are most appropriate for analyzing customer review text and uploaded product photos?

Unstructured data using natural language processing and computer vision

Which cloud-source limitation is illustrated when a team can access its database only while connected to the internet?

Internet dependence

What is missing when a database connection fails because the system cannot verify the user?

Authentication credentials

Which spreadsheet practice makes branch files easiest to combine in Power BI?

Keep one header row and consistent column names

When combining a distributor's sales records with government agricultural statistics and weather forecasts, which data is external?

The government statistics and weather forecasts

How should point-of-sale transactions, inventory records, and loyalty-card data from a supermarket be classified?

Internal sources because they originate within the organization

Which cloud limitation is responsible when REST API reports stop refreshing after too many requests?

API request limits

Which ETL stage occurs when storing cleaned booking records into a data warehouse for reporting?

Load

Which connection mode should be used when a retail dashboard must query a central SQL database upon user interaction rather than storing a local copy?

Direct query

What challenge is demonstrated when date formats MM/DD/YYYY and DD/MM/YYYY cause incorrect monthly totals after integration?

Format differences

What should an analyst do in Power Query when overlapping file combinations produce duplicate Order ID rows?

Select the identifying columns and choose Remove Duplicates

Which Power Query tool maps category variations like 'Female', 'F', and 'Woman' into one approved standard?

Replace Values or a Conditional Column

What is the appropriate action when delivery records have blank statuses that mean 'awaiting review'?

Replace the blank with “Pending Verification”

What action fixes dates stored as text that appear in alphabetical rather than chronological order?

Convert the column to the Date data type

Which operation combines 500 rows from January Sales and 450 rows from February Sales into one 950-row table?

Append Queries

How should a quantity value of -5 be classified when product quantities cannot be negative?

An invalid or incorrect value

Which cleaning action should be performed when a report treats 'Metro Manila', 'NCR', and 'National Capital Region' as three separate regions?

Standardize the category values

What is the most defensible treatment when a dataset lacks customer IDs essential for linking transactions?

Remove or isolate those records because a critical value is missing

What step must be taken before appending two monthly tables that use 'Order Amount' in one and 'Sales Value' in the other?

Standardize the corresponding column names

Which data type is most suitable for precise currency calculations on product prices?

Fixed decimal number

Which Power Query operation adds Name and City from a Customers table to matching records in an Orders table?

Merge using Customer ID as the matching field

Which data type is appropriate for Student IDs (e.g., 00127) that require leading zeros and are not used in math?

Text

Why is replacing uncaptured order amounts with zero without verification risky?

Zero may incorrectly imply that the order had no monetary value

Which principle guides review when a cleaned dataset still produces broken relationships and misleading charts?

Analysis quality depends heavily on source-data quality

Which Power Query operation removes unwanted spaces in text like ' Cebu City '?

Trim and Clean

Which Power Query feature corrects date parsing when 05/06/2026 is incorrectly interpreted as May 6 instead of 5 June?

Change Type Using Locale

Which join type retains all rows from Orders and matching customer details, while keeping orders without customer matches?

Left outer join with Orders as the left table

In database and data warehouse analysis, what are evaluated values such as sales amount, quantity sold, and profit called?

Measures

Which repository is best suited for shared definitions and cross-department analysis across an entire enterprise?

An enterprise data warehouse

In the five-layer data warehouse architecture, which layer contains reports and Power BI dashboards?

Presentation layer

Which processing approach is required for rapid, accurate transaction recording in transactional databases?

OLTP

Which processing approach is used when querying years of records to compare performance across branches and customer groups?

OLAP

What is a smaller repository that receives curated data from an enterprise data warehouse for use by a single department?

Finance data mart

Retaining five years of historical reservation data for seasonal analysis illustrates which data warehouse characteristic?

Time-variant

Organizing data warehouse information around subjects like customers, products, sales, and students demonstrates which characteristic?

Subject-oriented

Which EDW benefit addresses conflicting reports caused by different departments defining terms differently?

It establishes common definitions and standards

Converting source system customer codes into one unified standard before loading into a data warehouse demonstrates which characteristic?

Integrated

Which OLAP operation is performed when selecting ranges from multiple dimensions (e.g., product, location, time)?

Dice

Which data warehouse characteristic describes reading historical records without routine transactions continually overwriting past values?

Non-volatile

In OLAP analysis, what do fields like branch, product category, hour, and day of the week represent?

Dimensions

Which OLAP operation moves from annual sales totals down to quarterly, monthly, and daily results?

Drill down

Which OLAP operation restricts a multidimensional report by filtering down to a single dimension value (e.g., sales for 2026 only)?

Slice

What role does a product dimension table containing Product Key, Product Name, Category, and Brand serve?

It stores descriptive information for filtering and grouping

What must a modeler do before creating a relationship between two key columns stored with different data types?

Use compatible data types for both key columns

Why must a primary key column in a dimension table be corrected if it contains duplicates or blanks?

A primary key must uniquely identify each row and should not be blank

Which data modeling schema is generally preferred for simple relationships, clear filter paths, and efficient analytical queries?

A star schema

What design guidance should be followed when bidirectional relationships create multiple filter routes between tables?

Prefer single-direction filtering and avoid circular relationship paths

Mixing monthly balances with individual transactions in the same fact table neglects which key modeling decision?

Fact table grain

What key roles are assigned when DimProduct contains unique ProductKeys and FactSales contains thousands of repeated ProductKeys?

DimProduct[ProductKey] is primary; FactSales[ProductKey] is foreign

In the question 'What were total smartphone sales in Cebu during September?', which table provides the aggregated value and which dimension identifies smartphones?

FactSales provides the aggregated value; DimProduct identifies smartphones

If a model produces unexpected totals because two tables with repeated keys were connected directly, which relationship type should be investigated first?

Many-to-many

What type of table contains fields like Sale ID, Date Key, Product Key, Quantity, Discount, Cost, and Sales Amount?

Fact table

How should a report author clean up a model containing exposed technical key columns, unused fields, and implicit aggregations?

Hide technical keys, remove unused fields, and create explicit DAX measures

Which schema separates product, category, and department into individual related dimension tables to eliminate repeated descriptions?

Snowflake schema