WGU D492 CompTIA Data+ Latest updated version with accurate solutions 2026

Data Lake

a centralized repository designed to store, process, and secure large amounts of structured, semistructured, and unstructured data.

Data Lakehouse

Data lakehouses are a combination of a data warehouse and data lakes. They provide a cost-effective and flexible solution for data storage needs, but are not focused on transactional data.

OLTP (online transaction processing)

a technology used for real-time data queries and record creation

OLAP (online analytical processing)

a class of software that allows complex analysis to be conducted on large databases without affecting transactional systems

Data Mart

A data mart is a data storage technology used for specific departments or needs within a company - A subject-oriented relational database that stores transactional data in rows and columns, which makes it easy to access, organize, and understand. As it contains historical data, this structure makes it easier for an analyst to determine data trends

quantitative (discrete)

countable and with a limited number of values

quantitative (continuous)

measurable and can use any value

qualitative (nominal)

has no natural order ex. pink, green, brown

qualitative (ordinal)

follows a natural order ex. bad, good, great

SQL

direct interaction with the database

HTML

web pages

XML (Extensible Markup Language)

sending of data to and from another system

JSON (JavaScript Object Notation)

key value pairing of data between two web applications

delimited file

a delimited flat file contains one or more records set off from each other by a specified delimiter, or separator

synchronous

must wait for the response for requests from the web service

Asynchronous

allows you to do other tasks while waiting for the response

web scraping

the act of extracting data from a website (last resort, get permission)

machine data

data generated by the web servers - can be used for predictive maintenance

sampling

creating a smaller data set from a larger data set

data profiling

the process of checking information that is present in the data

1. identify and document the source of data

2. identify the field names and data types

3. determine the fields to be identified for reporting

4. check for the primary, natural, or foreign keys

5. recognize all the data in the data set

parametric

Data with an underlying normal distribution

nonparametric

Data for which the probability distribution is unknown or known not to be normal

noise

Unnecessary data fields that have no value to the analysis

data manipulation

the process of recoding data so that it can be more useful during our processing, correlation, analysis, and reporting

derived variable

a new variable or data point derived or created from existing data

recoded data

transforming data

data imputation

substitutes missing data with estimated values

index field

a unique, non-personally identifiable number that can be used a unique identifier

transposing data

swapping columns for rows, and rows for columns

appending data

combines data from one data set to another data set

inline append

combines data sets together (discards original)

intermediate append

retains individual data sets, but also creates a new data set with the combined data (keeps original)

data blending

takes data and uses different text-based functions to determine how it will be displayed or stored inside a data environment

conditional logic

any kind of function that checks if there is a logical condition that's being met (if, isnull, and, or)

IF

is a logical function that uses a logical test to validate whether a condition is true or false

ISNULL

returns a specified value if the expression is null

AND

a logical join function that tests two conditions

OR

tests if either one of two conditions is true

system functions

any functions that are packaged with your reporting tool or analysis tool to perform certain functions inside of that software

aggregate functions

written for a group of records, not just for a single record, and work with a column of data

data functions

derive attributes from date fields, like determining the day of the week, month, or year from a single date

indexing

a field property setting that improves query speed and performance for fields that are commonly queried, sorted, or filtered

parsing

breaks and extracts data out of a field for use

inner join

selects records that have matching values in both tables

left outter join

the matching data in the right, but all the data on the left whether it matches or not

right outter join

the matching data in the left, but all the data on the right whether it matches or not

full outter join

everything that intersects, as well as the rest of the data from both sides

cross outter join

It joins every row of the first table with every row of the second table, resulting in a potentially very large result set

parameterization

the concept of replacing values within the query with parameters

temporary table

a table that just resides in memory on the database

subquery

a query nested inside another query statement

actual execution plan

confirms the requirements used for a query

estimated execution plan

is a list of possible requirements for executing a query

exploratory analysis

the goal is to figure out what type of cleaning, profiling and transformation the data needs - it's all about the initial look at a given data set

performance analysis

type of analysis that measures the performance of a particular product, outcome, or scenario against the defined objective

KPIs (Key Performance Indicators)

measurements and goals that help identify whether a business is achieving its objectives (qualitative or quantitative)

gap analysis

analyzes the difference between the present state and a desired or future state (mostly quantitative measures)

delta

the change between where you are and where you want to be

trend analysis

measures the trend on historical data to predict a future outcome

link analysis

determines how a single data point links to other data points

finding standing deviation for SAMPLE

find the mean, subtract the mean to get the differences, square the differences, get the "mean" of those differences (this is the variance). The standard deviation is the squared root of the variance. with SAMPLE, its the number of samples -1

z-score

frequency

number of times that the given data value appears in the dataset

percentage difference

overall difference relative to the mean of two data points. b6-b5/average(b5+b6/2) *100

percentage change

(b6-b5)/b5*100

T-test

compares two groups to determine if there's a significant difference between their means

P-value

shows the probability that an observed difference occurred by chance (you want lower than 5%)

null hypothesis

assumes that there is NO relationship between the two variables being tested

alternative hypothesis

assumes that there is a relationship between the two variables being tested

type I error

false positive

type II error

false negative

chi-square statistic

compares the size of the difference between the expected result and the actual result

regression analysis

Statistical method used to estimate relationships between a dependent variable and one or more independent variables

pie chart

to show percentages

tree map

made for representing hierarchical data

bar chart

values on the x axis

column chart

values on the Y axis

line chart

time based data

scatter plot

to see if your data fits a trend

bubble chart

A type of scatter plot with circular symbols used to compare three variables; the area of the circle indicates the value of a third variable

Histogram

A graph of vertical bars representing the frequency distribution of a set of data. (no spaces)

waterfall chart

we're looking at discrete events over time

and seeing how each event

plays off the previous event before it

and adds or subtracts from where it left you

stacked chart

The stacked column/bar chart breaks a bar or column into separate portions to represent each data point

static report

report that is not automatically updated

real-time reporting

occurs when receiving up-to-date data

ad hoc report

generated in response to a one-time request

paginated report

a multi-page report that is not suitable for display on a dashboard

wireframe

a series of multiple mockups for multiple screens that are likely connected on a dashboard

narrative

a summary of the report contents and key findings

data creation

when data is acquired, entered, or captured in the system

data acquisition

occurs when existing data is produced outside and imported automatically to the system

data entry

occurs when information is manually typed into the system

data capture

occurs when data is generated by a device into the organization

data storage

occurs when data is not being actively used

data use

viewing, processing, modifying, manipulating or saving the data

data archival

copying and storing of data that can be used when needed

data destruction

when the data is no longer valuable or has reached its useful life and needs to be destroyed

data steward

the person responsible for ensuring data is properly labeled, identified, collected, and stored

data custodian

a role that's responsible for handling the management of the system on which the data assets are going to be stored

data sovereignty

A term that refers to the legal implications of data stored in different countries or states