Data Fundamentals
What does each letter in SQL mean
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
This tells SQL how to sort the data that is selected.
Group By
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.
The popular function used to look up a value in the first column of a range and return a value from a specified column in the same row.
What is VLOOKUP