Ways to improve the performance of Tableau

👉🏻 Use an Extract to make workbooks run faster.
👉🏻 Reduce the number of marks on the view to avoid information overload.
👉🏻 Hide unused fields.
👉🏻 Use Context filters.
👉🏻 Use indexing in tables and use the same fields for filtering.
👉🏻 Remove unnecessary calculations and sheets.

Requirements for data analyst based on some job profiles from @getjobss channel

👉 Strong data handling, data modeling & data flow understanding

👉 Ability to write complex queries on SQL to manipulate, consolidate multiple data sources for the purpose of dashboarding and analysis

👉 Intuition for data and ability to handle big data sources

👉 Strong working knowledge in Excel and visualization tools like PowerBI, Tableau, QlikView

👉 Ability to work on ambiguous tasks, find suitable solutions, and seek help/advice where appropriate.

1. Define the term 'Data Wrangling.

Data Wrangling is the process wherein raw data is cleaned, structured, and enriched into a desired usable format for better decision making. It involves discovering, structuring, cleaning, enriching, validating, and analyzing data. This process can turn and map out large amounts of data extracted from various sources into a more useful format.

2. What are the best methods for data cleaning?

Create a data cleaning plan by understanding where the common errors take place and keep all the communications open. Before working with the data, identify and remove the duplicates. This will lead to an easy and effective data analysis process.Focus on the accuracy of the data. Set cross-field validation, maintain the value types of data, and provide mandatory constraints.Normalize the data at the entry point so that it is less chaotic. You will be able to ensure that all information is standardized, leading to fewer errors on entry.


3. Explain the Type I and Type II errors in Statistics?

In Hypothesis testing, a Type I error occurs when the null hypothesis is rejected even if it is true. It is also known as a false positive.

A Type II error occurs when the null hypothesis is not rejected, even if it is false. It is also known as a false negative.

4. How do you make a dropdown list in MS Excel?

First, click on the Data tab that is present in the ribbon.Under the Data Tools group, select Data Validation.Then navigate to Settings > Allow > List.Select the source you want to provide as a list array.

5. State some ways to improve the performance of Tableau?

Use an Extract to make workbooks run faster.
Reduce the scope of data to decrease the volume of data.
Reduce the number of marks on the view to avoid information overload.
Hide unused fields.
Use Context filters.
Use indexing in tables and use the same fields for filtering.
Remove unnecessary calculations and sheets.

🗂The order of operations used in MS Excel while evaluating formulas

MS Excel follows a standard math protocol to evaluate a formula.

This protocol is called “order of operations” – PEMDAS –

~Parentheses
~Exponents
~Multiplication
~Division
~Addition
~Subtraction

MS Excel also applies some customization to handle the formula syntax.

The order in which MS Excel performs calculations can affect the return value of the formula.

First of all, Excel evaluates any expressions in parentheses.

As we have seen in mathematical formulae too, parentheses essentially override the normal order of operations. It prioritizes certain operations.

Next, Excel resolves cell references like A1 (cell address). It evaluates range references like A1:A10, making them arrays of values.

It also performs range operations like a union (comma) and an intersection (space).

Next, Excel performs –

-Exponentiation
-Negation
-% conversions
-Multiplication and division
-Addition and subtraction
-Concatenation
-Logical operators