Interview Questions and Answers

The probability of getting both heads when a coin is tossed 2 times is 1/4. If the coin is biased, the probability may change.

• The probability of getting both heads in a fair coin toss is 1/4 (1/2 * 1/2).

• If the coin is biased, the probability of getting both heads may be different depending on the bias.

• For example, if the coin is biased towards heads with a probability of 0.6, the probability of getting both heads would be 0.6 * 0.6 = 0.36.

Views are virtual tables that display data from one or more tables, while temp tables are temporary tables that store data temporarily.

• Views are virtual tables created by a query, while temp tables are physical tables created in the database.

• Views do not store data themselves, but display data from underlying tables, while temp tables store data temporarily for a session or transaction.

• Views can be used for security purposes by restricting access to certain columns or rows, w...read more

Types of bar charts in Tableau include standard bar, stacked bar, and side-by-side bar.

• Standard bar chart displays individual bars for each category

• Stacked bar chart shows the total value broken down into sub-categories

• Side-by-side bar chart compares multiple measures across categories

• Example: Stacked bar chart can be used to show sales by region, with each region broken down by product category

Tree map displays hierarchical data using nested rectangles, while heat map shows data values using color intensity.

• Tree map visualizes hierarchical data with nested rectangles, where the size of each rectangle represents a measure.

• Heat map displays data values using color intensity, with darker colors indicating higher values.

• Tree map is useful for showing proportions within a whole, while heat map is effective for identifying patterns and trends in data.

• Example: A tree map ...read more

Data blending combines data from different sources in Tableau, while joins combine data from the same source.

• Data blending is used when data comes from different sources and cannot be joined directly.

• Joins are used when data comes from the same source and can be combined based on a common key.

• Data blending allows for more complex analysis by combining unrelated data sets.

• Joins are more efficient for combining related data sets with a common key.

• Example: Data blending can be u...read more

WHERE is used to filter rows before grouping, HAVING is used to filter groups after grouping.

• WHERE is used with SELECT statement to filter rows based on a condition

• HAVING is used with GROUP BY statement to filter groups based on a condition

• WHERE is applied before grouping, HAVING is applied after grouping

• Example: SELECT * FROM table WHERE column = 'value'

• Example: SELECT column, COUNT(*) FROM table GROUP BY column HAVING COUNT(*) > 1

Parameters in Tableau allow users to control the values in a visualization without modifying the underlying data.

• Parameters can be used to filter data, change calculations, or modify the appearance of a visualization.

• They can be created by defining a parameter in Tableau and then using it in calculated fields or filters.

• Parameters can be set to different data types such as string, integer, float, date, etc.

• Users can interact with parameters through drop-down menus, sliders, o...read more

Metrics used in retail business include sales, customer acquisition cost, customer lifetime value, inventory turnover, and gross margin.

• Sales: Total revenue generated from products or services sold

• Customer acquisition cost: Cost incurred to acquire a new customer

• Customer lifetime value: Predicted revenue a customer will generate over their lifetime

• Inventory turnover: Number of times inventory is sold and replaced in a given period

• Gross margin: Percentage of revenue that excee...read more