Free TDA-C01 sample questions

Correct answer: WINDOW_STDEV(SUM([Stock Price]), -29, 0)

The `WINDOW_STDEV` function is a table calculation specifically designed to compute the standard deviation over a moving window of data. The arguments `(SUM([Stock Price]), -29, 0)` correctly define the aggregation and the window, which includes the current day and the 29 preceding days, making a 30-day rolling period. `STDEV()` is a regular aggregation and calculates the standard deviation for the entire partition. The `FIXED` LOD would calculate the standard deviation for each stock ticker across all time, not a rolling window.

Correct answer: A live connection.

A live connection queries the underlying database directly. This is the ideal choice when data freshness is critical and the database is performant enough to handle the query load from dashboard interactions. An extract, even if refreshed frequently, introduces latency as it is a snapshot of the data. A published data source on Tableau Server still requires a connection type, and a data blend is for combining different data sources, not for ensuring data freshness.

Correct answers: Sets; Set Actions

Sets are necessary to group the selected category ('IN' the set) versus all other categories ('OUT' of the set). This grouping is fundamental to creating the two separate trend lines.

Set Actions provide the interactivity, allowing a user's click or selection on the dashboard to dynamically change the members of the set. This action will drive which category is considered 'selected' for the comparison.

Correct answer: True

This is true. Tableau Server itself cannot use the credentials of the viewing user to connect to a data source that requires integrated authentication. Instead, an administrator must configure a specific 'Run As User' account. This account has the necessary permissions to the database, and Tableau Server will use this single account for all queries to that data source, acting on behalf of the end-users.

Correct answer: A Join step on ProductID.

A Join step is used to combine data from two tables based on a common field. In this case, both the order details and product information tables contain the `ProductID` field. By joining on this common field, the analyst can append columns from the product table (like `ProductName` and `Category`) to the rows of the order details table, creating the desired wide-format output. A Union stacks rows on top of each other, which is incorrect here.

Correct answer: In the data source pane, join the shipments table to the `CompanyHolidays` table using a left join where `HolidayDate` is between `ShipmentDate` and `DeliveryDate`. Then, use a calculation like `DATEDIFF('weekday', [ShipmentDate], [DeliveryDate]) - COUNTD([HolidayDate])` to get the business days.

This is the most robust solution. By performing a left join in the data source pane with a non-equi join condition (`HolidayDate` >= `ShipmentDate` AND `HolidayDate` <= `DeliveryDate`), you can identify all holidays that fall within a shipment's transit time. The `DATEDIFF('weekday', ...)` function correctly calculates the number of weekdays between two dates. Finally, subtracting the distinct count of holidays (`COUNTD([HolidayDate])`) from the weekday count gives the precise number of business days. This approach offloads the complex logic to the database layer and is more scalable than complex IF statements or data blending for this row-level task.

Correct answer: A quick table calculation for 'Percent of Total', computed using 'Pane (Down)'.

When `Category` and `Sub-Category` are placed on the shelves (e.g., Rows), Tableau partitions the view into 'panes' for each Category. A quick table calculation for 'Percent of Total' with its scope set to 'Pane' will calculate the sum of sales for each Sub-Category as a percentage of the total sales within its pane (i.e., its parent Category). 'Table (Across)' would calculate the percentage based on the grand total for the entire table. An LOD would also work, but the table calculation is more direct for this specific visual layout.

Correct answer: Add a 'Region' filter from one worksheet to the dashboard, then in its context menu, select 'Apply to Worksheets' > 'All Using This Data Source'.

The most efficient method is to add the filter from one of the worksheets to the dashboard. Then, by accessing the filter's context menu (the dropdown arrow), you can specify its scope. Choosing 'All Using This Data Source' will make this single filter control every other worksheet on the dashboard that is built from the same data source. This avoids creating redundant filters or complex filter actions.

Correct answer: The diagram is correct.

The diagram accurately represents Tableau's filter order of operations. Filters are applied sequentially from the broadest to the most specific. Extract filters are applied first when the extract is created. Data source filters are next, restricting data at the source level. Context filters create a temporary table that all subsequent filters run against, so they come next. Finally, standard dimension filters are applied before the view is rendered.

Correct answers: Use a single, long, vertical layout to facilitate scrolling.; Place the most important KPIs and summaries at the top of the view.; Limit the number of filters and use larger, more touch-friendly filter controls.

Mobile users are accustomed to scrolling. A single vertical layout is easier to navigate on a small screen than a wide, multi-column layout.

To provide information quickly, key metrics and summaries should be visible without requiring the user to scroll down.

Screen real estate is limited on mobile devices. Minimizing filters and making the controls larger (e.g., single value lists instead of compact lists) improves usability.