Explain The Knn Imputation Method In Brief
KNN is the method that requires the selection of several nearest neighbors and a distance metric at the same time. It can predict both discrete and continuous attributes of a dataset.
A distance function is used here to find the similarity of two or more attributes, which will help in further analysis.
What Are The Different Types Of Connections Available In Tableau Software
Tableau software has gained prominence among data analysts and scientists in the last few decades. The software is believed to be the worlds broadest and deepest data analytical tool, which is being adopted by many companies worldwide into their data analysis process. With this question, the interviewer wants to test your theoretical knowledge about the software.
What Are The Different Connection Types In Tableau Software
There are mainly 2 types of connections available in Tableau.
Extract: Extract is an image of the data that will be extracted from the data source and placed into the Tableau repository. This image can be refreshed periodically, fully, or incrementally.
Live: The live connection makes a direct connection to the data source. The data will be fetched straight from tables. So, data is always up to date and consistent.
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What Are The Ways To Detect Outliers Explain Different Ways To Deal With It
Outliers are detected using two methods:
- Box Plot Method: According to this method, the value is considered an outlier if it exceeds or falls below 1.5*IQR , that is, if it lies above the top quartile or below the bottom quartile .
- Standard Deviation Method: According to this method, an outlier is defined as a value that is greater or lower than the mean ± .
How Do You Treat Outliers In A Dataset
An outlier is a data point that is distant from other similar points. They may be due to variability in the measurement or may indicate experimental errors.
The graph depicted below shows there are three outliers in the dataset.
To deal with outliers, you can use the following four methods:
- Drop the outlier records
- Try a new transformation
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In Your Role As A Data Analyst Have You Ever Recommend A Switch To Different Processes Or Tools What Was The Result Of Your Recommendation
How to Answer
For hiring managers, its important that they pick a data analyst who is not only knowledgeable but also confident enough to initiate a change that would improve the companys status quo. When talking about the recommendation you made, give as many details as possible, including your reasoning behind it. Even if the recommendation you made was not implemented, it still demonstrates that youre driven and you strive for improvement.
Although data from non-technical departments is usually handled by data analysts, Ive worked for a company where colleagues who were not on the data analysis side had access to data. This brought on many cases of misinterpreted data that caused significant damage to the overall company strategy. I gathered examples and pointed out that working with data dictionaries can actually do more harm than good. I recommended that my coworkers depend on data analysts for data access. Once we implemented my recommendation, the cases misinterpreted data dropped drastically.
What Is The Use Of And Function In Excel
With this question, the interviewer is trying to test your knowledge about different Excel functions. For the unversed, AND is a logical function that checks multiple conditions and reveals whether the conditions stated are TRUE or FALSE. This function is widely used in data analysis, and hence an aspiring data analyst should be well-versed with it.Although Excel is a software that everyone has been using since elementary school, there are many minute details about the software that remain untapped, such as the formula section that professionals only use for office work. Therefore, learn the nitty-gritty of the software before attending the interview round because you can expect questions like- explaining how VLOOKUP works in excel, what function will you use to get the current date and time, and others.
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What Is The Difference Between A Shallow And A Deep Copy
|Shallow Copy||Deep Copy|
|It constructs a new compound object and then inserts references into it to the objects found in the original.||It constructs a new compound object and then, recursively, inserts copies into it of the objects found in the original.|
|Shallow copy is used to copy the reference pointers just like it copies the values.||It makes the reference to an object and the new object that is pointed by some other object gets stored.|
|These references point to the original objects and the changes made in any member of the class will also affect the original copy of it.||The changes made in the original copy wont affect any other copy that uses the object.|
|It allows faster execution of the program and it depends on the size of the data that is used.||It makes execution of the program slower due to making certain copies for each object that is being called.|
What Is The Most Challenging Project Youve Encountered On Your Learning Journey
A good answer for this question is a project that deviated from the typical Excel use-cases you originally studied. This might be the first project you encountered that required creative thinking and custom solutions in order to achieve its goal. Your ability to manipulate the software to your needs in such a situation will show your mastery of Excel fundamentals and your problem-solving skills, as well as a good work attitude.
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What Are The Questions You Would Consider Before Making A Chart And Dashboard
A dashboard is used to see a range of data at a glance, to help correlate data and make informed decisions without having to manually find and re-find the data you need to compare and contrast. For this reason, a dashboard works best when created to answer a certain question, or help make a certain decision.
Think about the decision you want to make and all the data that would play a part in informing that decision. If you were trying to settle on a type of fabric to make t-shirts out of, for example, and had many worksheets of data on the price, dye quality, allergens, strength, softness, resourcing, and emissions of different fabric types, making a dashboard with all this information would help you make an informed decision. You would be able to easily see which fabrics have a good result in every field, and pick the best for the job.
How Do You Use Vlookup
The VLOOKUP syntax is composed of the lookup value, the range of data in which the lookup value is located, and the column number within this range that contains the desired return value. You can also specify whether you want an approximate match or an exact match to be returned, but this step is optional.
In other words, you must first indicate the cell reference of the value you would like to search for. Next, indicate the range of data you would like to search for . You can then specify the column that contains the information you seek and input it as a number .
To indicate whether the return value should be approximate or exact, finish the formula with TRUE or FALSE . An example formula would look like this: =VLOOKUP.
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What Is A Pareto Chart And When Do We Use It How Do You Create It In Tableau
Pareto Chart is based on the Pareto rule that states that 80% of output comes from 20% of the input. It is used when we want to check how much input factor is contributing to the output.
In Tableau, the Pareto chart is created using the following steps:
Q: Name A Few Data Analysis Tools You Use
Your knowledge of the open-source and paid data analytics tools will allow them to know you are a frequent user and active in your practices. Data analytics tools are greatly beneficial to ease the entire process of acquisition, cleaning, and presentation of data, so pick the tools that work best for you. Here are a few of them-
- Apache Spark
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Using The Data Given Below Create A Pivot Table To Find The Total Sales Made By Each Sales Representative For Each Item Display The Sales As % Of The Grand Total
- Select the entire table range, click on the Insert tab and choose PivotTable
- Select the table range and the worksheet where you want to place the pivot table
- Drag Sale total on to Values, and Sales Rep and Item on to Row Labels. It will give the sum of sales made by each representative for every item they have sold.
- Right-click on Sum of Sale Total and expand Show Values As to select % of Grand Total.
- Below is the resultant pivot table.
What Is The Difference Between Append And Extend
When the append method adds its argument as a single element to the end of a list, the length of the list itself will increase by one.
On the other hand, extend method iterates over its argument adding each element to the list, extending the list.
Example: list1 =
Output: list1 =
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Additional Situational Interview Questions For Data Analysts
|What are your top communication skills?|
|Please provide an example of a situation in which you demonstrated leadership capabilities on the job?|
|Describe a time when you had to persuade others. How did you get buy-in?|
|Please provide a self-assessment of your writing skills? As a Data Analyst, why is written communication important?|
|Have you ever had to present to an audience of stakeholders who didnt understand data analysis or what a Data Analyst does? How did you explain your insights and processes?|
Q2 How Can You Highlight Cells With Negative Values In Excel
You can highlight cells with negative values in Excel by using the conditional formatting. Below are the steps that you can follow:
- Select the cells which you want to highlight with the negative values.
- Go to the Home tab and click on the Conditional Formatting option
- Go to the Highlight Cell Rules and click on the Less Than option.
- In the dialog box of Less Than, specify the value as 0.
Fig 3: Snapshot of Highlighting cells in Excel Data Analyst Interview Questions
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Mention The Difference Between Data Profiling And Data Mining
Answer:The difference between data profiling and data mining is:
Data Profiling is aimed at individual attributes analysis. Information on different attributes like discrete values, value ranges and their data type, frequency, length are gotten from it. Data mining, on the other hand, targets unusual records detection, cluster analysis, sequence discovery and others.
Have You Ever Created Or Worked With Statistical Models If So Please Describe How Youve Used It To Solve A Business Task
How to Answer
As a data analyst, you dont specifically need experience with statistical models, unless its required for the job youre applying for. If you havent been involved in building, using, or maintaining statistical models, be open about it and mention any knowledge or partial experience you may have.
Being a data analyst, I cant say Ive had direct experience building statistical models. However, Ive helped the statistical department by making sure they have access to the proper data and analyzing it. The model in question was built with the purpose of identifying the customers who were most inclined to buy additional products and predicting when they were most likely to make that decision. My job was to establish the appropriate variables used in the model and assess its performance once it was ready.
Please Share Some Past Data Analysis Work Youve Doneand Tell Me About Your Most Recent Data Analysis Project
Danielle says: Its best to use the STAR method when asked a question such as this: Situation, Task, Action, Result. Outline the circumstances surrounding a previous data analysis project, describe what you had to do, how you did it, and the outcome of your work. Dont worry about being fairly rigid in your approach to this answerjust make sure the interviewer has everything they need to know by the end.
What Are The Perks Of Using The Excel Sheet Formula
When working on a workbook with lots of data and multiple sheets, the SHEET function can help the user search for particular segments of data. When a cell reference, named range, or Excel Table is entered as the value, the SHEET function will return the index number of the sheet that contains this value.
Excel includes hidden sheets in its numbering sequence. If a table named Profits1 is on the tenth sheet, the SHEET function will return 10. The formula will look like this: =SHEET.
Running the SHEET function without a value will return the index number of the current sheet . There is also a similarly named function SHEETSthis function returns the number of sheets in a workbook.
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How Do You Prepare For A Data Analyst Interview
The first thing that you need to do to prepare is to understand what the company youre applying to is trying to achieve with its data analysis efforts. Recruiters are quickly impressed when you show an understanding of the organizational context youll be working in.
After that, focus on your skills in regard to three things: data analysis math and stats, data analysis approaches, and data analysis tools. Finally, attempt practice questions like the ones weve covered here .
Basic Excel Interview Questions For Data Analysts
In this section, well cover a handful of basic Excel interview questions for data analysts, but even intermediate and advanced candidates should be prepared for the possibility of meeting a few of these questions. The fundamentals never lose their importance and your attitude towards them is something interviewers will take note of, so make sure to refresh your knowledge on the basics of what data analytics is, and the role Microsoft Excel plays in the industry.
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What Are The Best Practices For Data Cleaning
- In the case of massive datasets, do a stepwise cleansing and improve on the data on every step until the data quality is good.
- For common data cleansing, you need to generate a set of scripts which include blanking out every value not matching a regex.
- Do analysis on the statistic for every column.
- Stay up to date with all cleaning operations, so changes could make when necessary.
Whats Your Favourite Tool For Data Analysisyour Likes Dislikes And Why What Querying Languages Do You Know
Danielle says: For this question, Its important you detail your Excel skills, which are an integral part of performing data analysis. Prove your Excel credentials, outlining any courses youve been on or examples of analysis youve performed with the program. Employers will also want to know what querying languages youre familiar with, whether it be SAS, R, Python or another language. Querying languages are used for larger sets of data, so youll need to prove you have a solid foundation in one of these languages. Heres a top tip: try and find out what querying language the company youre applying to uses, that might come in handy!
What Is Vlookup
VLOOKUP is a predetermined function in Excel that allows the user to find data within a table corresponding to a particular row.
For instance, say you have a table of employee information that includes employee ID, employee name, start date, hours per week, and salary. With VLOOKUP you can specify a row from the first column and look up corresponding data from other columns, like the salary of the employee with that employee ID.
What Is An N
An n-gram is a method used to identify the next item in a sequence, usually words or speech. N-grams uses a probabilistic model that accepts contiguous sequences of items as input. These items can be syllables, words, phonemes, and so on. It then uses that input to predict future items in the sequence.
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How Is Overfitting Different From Underfitting
This is another frequently asked data analyst interview question, and you are expected to cover all the given differences!
|The model trains the data well using the training set.||Here, the model neither trains the data well nor can generalize to new data.|
|The performance drops considerably over the test set.||Performs poorly both on the train and the test set.|
Happens when the model learns the random fluctuations and noise in the training dataset in detail.
This happens when there is lesser data to build an accurate model and when we try to develop a linear model using non-linear data.