Data Fundamentals
What is the full form of SQL
Structured Query Language
What is missing data?
Data that is absent or not recorded in a dataset.
What is the purpose of a bar chart?
To compare different categories of data visually.
What does the mean represent in statistics?
The average value of a dataset.
What SQL command is used to retrieve data from a database?
SELECT
What is a primary key in a database?
A column or a set of columns that uniquely identifies each row in a table
What method is used to handle missing values in a dataset?
Imputation (mean, median, mode) or deletion.
What is a histogram used for?
To show the distribution of numerical data.
What is the median, and how is it different from the mean?
The middle value of a dataset; unlike the mean, it is not affected by outliers.
What symbol is used to start a formula in Excel?
=
What are the main types of data in statistics?
Numerical, Categorical
What is data normalization?
The process of scaling data to a standard range
What is the difference between a scatter plot and a line graph?
A scatter plot shows individual data points, while a line graph connects them to show trends.
What does standard deviation measure?
The spread or variability of a dataset.
What clause is used to filter results in an SQL query?
Where
What is the difference between structured and unstructured data?
Structured data is organized in a defined format like tables, while unstructured data lacks a predefined structure, such as images and videos.
Why is removing duplicate data important?
To prevent redundancy and ensure data integrity.
What is the main advantage of using a dashboard in data analytics?
It provides a visual summary of key metrics for quick decision-making.
What is the difference between correlation and causation?
Correlation shows a relationship between variables, while causation indicates that one variable directly affects another
What is the function to count the number of non-empty cells in a range?
COUNTA()
What is the difference between a table and a database?
A database is a collection of data organized in various tables, while a table is a collection of related data organized in rows and columns within a database.
What is outlier detection, and why is it important?
dentifying data points that significantly differ from others; important for improving data accuracy and analysis reliability.
How does a heatmap represent data?
Using colors to indicate the magnitude of values within a dataset.
What is hypothesis testing in statistics?
A method to determine if there is enough evidence to support a hypothesis about a dataset.
What is the XLOOKUP function, and how is it different from VLOOKUP?
XLOOKUP is a more advanced lookup function that replaces VLOOKUP and HLOOKUP. Unlike VLOOKUP, it can search in both directions (left or right) and does not require the lookup column to be the first column in the range.