Data Analytics

The best way to learn about AI is to build real projects with it. When you build, you learn what’s valuable and what’s not. Use GitHub, Kaggle, paperswithcode, YouTube tutorial and build a strong foundation around it. Develop a solid skillset and always remember there is no alternative to practice and hard work 💪

SQL Notes 👇👇 https://t.me/datasciencefun/1198

1.How would you track down the last line and segment in VBA? To track down the last column, utilize the underneath lines code in the VBA module: Sub FindingLastRow() Faint lastRow As Long lastRow = ActiveSheet.Cells.SpecialCells(xlLastCell).Row MsgBox (lastRow) End Sub To track down the last section, utilize the beneath lines code in the VBA module: Sub FindingLastColumn() Faint lastRow As Long lastColumn = ActiveSheet.Cells.SpecialCells(xlLastCell).Column MsgBox (lastColumn) End Sub 2.How to increase size of pie in tableau? Creating a pie chart requires atleast one measure and one dimension in row and shelf column. Then you can select a pie chart from either the show me option on the right side of the screen or from the marks card change automatic to pie. Then give some detailing to the pie chart by using a dimension in colour and measure in angle. Option to increase the size also comes under marks card. Click on the size option and then move the slider towards right to increase its size. 3.How to calculate the average in Power BI? Average can be calculated in two ways- one is when we add a measure to a visual; by default, it summarizes any measure. When we click on the drop-down for the measure- we can change from Sum to Average. This gives us an average. The second one is creating a calculated measure for average using the AVERAGE() DAX function. 4.Where is the data stored in Power BI? The nation or area for the business identity is chosen by the first user in your organization who signs up for Power BI or Microsoft 365. The cloud’s shared identity and access management service, Azure Active Directory (AAD), establishes a tenant in the data center region nearest to the chosen nation or area. AAD is a multi-tenant service, with each enterprise represented in the data center as a separate tenant. The data is saved in the area you choose at sign-up. This region will be the same for all users in your organization, regardless of their location. The chosen region should, ideally, be in the same geographical area as the majority of your consumers.

Data Scientist RoadMap https://t.me/datasciencefun/1142

1. What is the difference between supervised learning and unsupervised learning? Give concrete examples. Supervised learning involves learning a function that maps an input to an output. For example, if I had a dataset with two variables, age (input) and height (output), I could implement a supervised learning model to predict the height of a person based on their age. Unlike supervised learning, unsupervised learning is used to draw inferences and find patterns from input data without references to labeled outcomes. A common use of unsupervised learning is grouping customers by purchasing behavior to find target markets. 2.How do you assess the statistical significance of an insight? Ans: You would perform hypothesis testing to determine statistical significance. First, you would state the null hypothesis and alternative hypothesis. Second, you would calculate the p-value, the probability of obtaining the observed results of a test assuming that the null hypothesis is true. Last, you would set the level of the significance (alpha) and if the p-value is less than the alpha, you would reject the null — in other words, the result is statistically significant. 3. What is the Law of Large Numbers? Ans: The Law of Large Numbers is a theory that states that as the number of trials increases, the average of the result will become closer to the expected value. Eg. flipping heads from fair coin 100,000 times should be closer to 0.5 than 100 times. 4.If a Company says that they want to double the number of ads in Newsfeed, how would you figure out if this is a good idea or not? Ans: You can perform an A/B test by splitting the users into two groups: a control group with the normal number of ads and a test group with double the number of ads. Then you would choose the metric to define what a “good idea” is. For example, we can say that the null hypothesis is that doubling the number of ads will reduce the time spent on Facebook and the alternative hypothesis is that doubling the number of ads won’t have any impact on the time spent on Facebook. However, you can choose a different metric like the number of active users or the churn rate. Then you would conduct the test and determine the statistical significance of the test to reject or not reject the null.

1.What is a heatmap? Give an example. A heatmap is a type of visualization used to demonstrate a set of data through varying shades of colours where the darkest shade of a specific colour denotes an extreme value (high intensity/density). It is typically used to compare two or more measures. A quick example of a heatmap would be to understand the anatomy of the human body and observe the level of warmth depending upon the temperature of specific organs. If the red-yellow combination of colours is used, the areas that show red will denote the maximum temperature. 2. What is DRIVE Program Methodology? It is a product of iterative sessions previously used and tested by enterprise deployments. It is based on best practises and allows a user to follow a specific set of actions to avoid errors and expedite reporting or visualization process. 3. When does regularization come into play in Machine Learning? At times when the model begins to underfit or overfit, regularization becomes necessary. It is a regression that diverts or regularizes the coefficient estimates towards zero. It reduces flexibility and discourages learning in a model to avoid the risk of overfitting. The model complexity is reduced and it becomes better at predicting. 4. What is the order of operations in Excel? Excel follows PEMDAS: parentheticals, exponents, multiplication, division, addition, and then subtraction. If you type in “=1+2/4” the answer will be 3/2 rather than ¾.

1. Explain data cleansing. Data cleaning, also known as data cleansing or data scrubbing or wrangling, is basically a process of identifying and then modifying, replacing, or deleting the incorrect, incomplete, inaccurate, irrelevant, or missing portions of the data as the need arises. This fundamental element of data science ensures data is correct, consistent, and usable.  2. What is an Affinity Diagram? Ans. An Affinity Diagram is an analytical tool used to cluster or organize data into subgroups based on their relationships. These data or ideas are mostly generated from discussions or brainstorming sessions and are used in analyzing complex issues. 3. Which questions should you ask the user/client before you create a dashboard? Though this depends on the user’s requirements, still some of the common questions that I would ask the client before creating a dashboard are : What is the purpose of the dashboard?Should the dashboard be retrospective or real-time?How detailed the dashboard should be?How tech and data-savvy is the end-user?Does the data need to be segmented?Should I explain the dashboard design to you? 4. What is an Alias in SQL? An alias is a feature of SQL that is supported by most, if not all, RDBMSs. It is a temporary name assigned to the table or table column for the purpose of a particular SQL query. In addition, aliasing can be employed as an confusion technique to secure the real names of database fields. A table alias is also called a correlation name. An alias is represented explicitly by the AS keyword but in some cases, the same can be performed without it as well.

Data Science Interview 👇👇 https://t.me/datasciencefun/998

1. How to change a table name in SQL? This is the command to change a table name in SQL: ALTER TABLE table_name RENAME TO new_table_name; We will start off by giving the keywords ALTER TABLE, then we will follow it up by giving the original name of the table, after that, we will give in the keywords RENAME TO and finally, we will give the new table name. 2. How to use LIKE in SQL? The LIKE operator checks if an attribute value matches a given string pattern. Here is an example of LIKE operator SELECT * FROM employees WHERE first_name like ‘Steven’; With this command, we will be able to extract all the records where the first name is like “Steven”. 3. If we drop a table, does it also drop related objects like constraints, indexes, columns, default, views and sorted procedures? Yes, SQL server drops all related objects, which exists inside a table like constraints, indexes, columns, defaults etc. But dropping a table will not drop views and sorted procedures as they exist outside the table. 4. Explain SQL Constraints. SQL Constraints are used to specify the rules of data type in a table. They can be specified while creating and altering the table. The following are the constraints in SQL: NOT NULL CHECK DEFAULT UNIQUE PRIMARY KEY FOREIGN KEY

IBM is hiring Data Analyst/ Data Engineer! https://t.me/getjobss/1394 Required Technical and Professional Expertise 👉 Minimum 0-1 year of experience in Know your customer, Customer due diligence & Customer identification program (KYC/CDD/EDD/CIP) 👉 Working knowledge in US/UK regulatory policies 👉 Proven ability to deal with highly personal, confidential information. 👉 Experience in financial services transaction data analysis 👉 Excellent English writing, reading and speaking skill. 👉 Good analytical and problem-solving skills.

POWERBI INTERVIEW QUESTIONS https://t.me/crackingthecodinginterview/571?single

( Master in SQL Guide 📖 ) DDL, DML, TCL, DCL, DQL https://t.me/learndataanalysis/308

1. What is Data Integrity? Data Integrity is the assurance of accuracy and consistency of data over its entire life-cycle and is a critical aspect of the design, implementation, and usage of any system which stores, processes, or retrieves data. It also defines integrity constraints to enforce business rules on the data when it is entered into an application or a database. 2. What is the Difference Between Joining and Blending in Tableau? Combining the data from two or more different sources is data blending, such as Oracle, Excel, and SQL Server. In data blending, each data source contains its own set of dimensions and measures. Combining the data between two or more tables or sheets within the same data source is data joining. All the combined tables or sheets contain a common set of dimensions and measures. 3. What is slicing in Python? As the name suggests, ‘slicing’ is taking parts of. Syntax for slicing is [start : stop : step] start is the starting index from where to slice a list or tuple stop is the ending index or where to stop. step is the number of steps to jump. Default value for start is 0, stop is number of items, step is 1. Slicing can be done on strings, arrays, lists, and tuples. 4. What is the difference between NOW() and CURRENT_DATE() in SQL? NOW() returns a constant time that indicates the time at which the statement began to execute. (Within a stored function or trigger, NOW() returns the time at which the function or triggering statement began to execute. The simple difference between NOW() and CURRENT_DATE() is that NOW() will fetch the current date and time both in format ‘YYYY-MM_DD HH:MM:SS’ while CURRENT_DATE() will fetch the date of the current day ‘YYYY-MM_DD’.

1. What are Query and Query language? A query is nothing but a request sent to a database to retrieve data or information. The required data can be retrieved from a table or many tables in the database. Query languages use various types of queries to retrieve data from databases. SQL, Datalog, and AQL are a few examples of query languages; however, SQL is known to be the widely used query language. 2. What are Superkey and candidate key? A super key may be a single or a combination of keys that help to identify a record in a table. Know that Super keys can have one or more attributes, even though all the attributes are not necessary to identify the records. A candidate key is the subset of Superkey, which can have one or more than one attributes to identify records in a table. Unlike Superkey, all the attributes of the candidate key must be helpful to identify the records. 3. What do you mean by buffer pool and mention its benefits? A buffer pool in SQL is also known as a buffer cache. All the resources can store their cached data pages in a buffer pool. The size of the buffer pool can be defined during the configuration of an instance of SQL Server. The following are the benefits of a buffer pool: Increase in I/O performance Reduction in I/O latency Increase in transaction throughput Increase in reading performance 4. What is the difference between Zero and NULL values in SQL? When a field in a column doesn’t have any value, it is said to be having a NULL value. Simply put, NULL is the blank field in a table. It can be considered as an unassigned, unknown, or unavailable value. On the contrary, zero is a number, and it is an available, assigned, and known value.

1. How to change a table name in SQL? This is the command to change a table name in SQL: ALTER TABLE table_name RENAME TO new_table_name; We will start off by giving the keywords ALTER TABLE, then we will follow it up by giving the original name of the table, after that, we will give in the keywords RENAME TO and finally, we will give the new table name. 2. Find the Constraint information from the table? There are so many times where user needs to find out the specific constraint information of the table. The following queries are useful, SELECT * From User_Constraints; SELECT * FROM User_Cons_Columns; 3. What is the difference between clustered and non-clustered indexes? Clustered indexes can be read rapidly rather than non-clustered indexes. Clustered indexes store data physically in the table or view whereas, non-clustered indexes do not store data in the table as it has separate structure from the data row. 4. What are the subsets of SQL? DDL (Data Definition Language): Used to define the data structure it consists of the commands like CREATE, ALTER, DROP, etc. DML (Data Manipulation Language): Used to manipulate already existing data in the database, commands like SELECT, UPDATE, INSERT DCL (Data Control Language): Used to control access to data in the database, commands like GRANT, REVOKE.

1. Explain data cleansing. Data cleaning, also known as data cleansing or data scrubbing or wrangling, is basically a process of identifying and then modifying, replacing, or deleting the incorrect, incomplete, inaccurate, irrelevant, or missing portions of the data as the need arises. This fundamental element of data science ensures data is correct, consistent, and usable.  2. What is an Affinity Diagram? Ans. An Affinity Diagram is an analytical tool used to cluster or organize data into subgroups based on their relationships. These data or ideas are mostly generated from discussions or brainstorming sessions and are used in analyzing complex issues. 3. Which questions should you ask the user/client before you create a dashboard? Though this depends on the user’s requirements, still some of the common questions that I would ask the client before creating a dashboard are : What is the purpose of the dashboard?Should the dashboard be retrospective or real-time?How detailed the dashboard should be?How tech and data-savvy is the end-user?Does the data need to be segmented?Should I explain the dashboard design to you? 4. What is an Alias in SQL? An alias is a feature of SQL that is supported by most, if not all, RDBMSs. It is a temporary name assigned to the table or table column for the purpose of a particular SQL query. In addition, aliasing can be employed as an confusion technique to secure the real names of database fields. A table alias is also called a correlation name. An alias is represented explicitly by the AS keyword but in some cases, the same can be performed without it as well.