Tableau Qualified Associate Exam
Trend Lines
- Show general direction or course of data - With trend lines you can answer such questions as whether profit is predicted by sales, or whether average delays at an airport are significantly correlated with the month of the year. - If the P-Value is greater than .05, then the trend line doesn't provide much predictive value. R-Squared provides an indicator of how well the line fits the individual marks. **** Tableau does the best job, it can fit the line to the plot, but if the marks are randomly scattered, the R- Squared value will be low. The combination of low P-Value and R-Squared value means that the trend line on the left side does not provide much predictive value.
Combo Chart
A chart that combines two chart types, such as column and line, to plot different types of data, such as quantities and percentages.
Reference Bands
A reference distribution adds a gradient of shading to indicate the distribution of values along the axis. Distributions can be defined by confidence interval, percentages, percentiles, quantiles, or standard deviation
Gantt Chart
A time and activity bar chart that is used for planning, managing, and controlling major programs that have a distinct beginning and end.
Exponential Smoothing
A weighted-moving-average forecasting technique in which data points are weighted by an exponential function. Exponential smoothing models iteratively forecast future values of a regular time series of values from weighted averages of past values of the series. The method is exponential because the value of each level is influenced by every preceding actual value to an exponentially decreasing degree—more recent values are given greater weight. ***The more data points you have in your time series, the better the resulting forecast will be. On the other hand, if you forecast using data generated by two or more different DGPs, you will get a lower quality forecast because a model can only match one.
Cross Database Joins
Allows users to join tables from different databases using the data source connections tabs.
Additive vs Multiplicative
An additive model is one in which the contributions of the model components are summed, whereas a multiplicative model is one in which at least some component contributions are multiplied. Multiplicative models can significantly improve forecast quality for data where the trend or seasonality is affected by the level (magnitude) of the data **a multiplicative model cannot be computed when the measure to be forecast has one or more values that are less than or equal to zero.
LOD Calculation: Fixed
Another way of saying "For each (dimension), give me their (measure)"
Bar in bar
Bar in bar charts provide a fantastic way to compare a measure against a goal or to display two measures against one another
Date fields in Tableau
DATEADD DATEDIFF DATENAME - Returns a part of the given date as a string, where the part is defined by date_part. Example: DATENAME('month', #2004-04-15#) = "April" DATEPARSE - converts a string to a date in the specified format. Example: DATAPARSE("dd.MMMM.yyyy", "15.April.2004") = 2004-04-15 12:00:00 AM DATEPART - Returns a part of the given date as an integer where the part is defined by date_part. Example: DATEPART('month', #2004-04-15#) = 4 DATETIME - gives the time of a date DATETRUNC - truncates the specified date to the accuracy specified by the date_part and returns the new date
Discrete vs. Continuous
Discrete (blue pills) - they contain a FINITE number of values - for example - the field REGION may contain the values North/South/East & West, but no others Continuous (green pills) - they could contain an infinite number of values - for example the PRICE of an item could be any value along a number line.
Blending Data
Do this as an alternative to joining data. This is to avoid duplicates within data sets. Data blending simulates a traditional left join. The main difference between the two is when the join is performed with respect to aggregation.
Forecasting in Tableau
Forecast algorithms try to find a regular pattern in measures that can be continued into the future. You typically add a forecast to a view that contains a date field and at least one measure. However, in the absence of a date, Tableau can create a forecast for a view that contains a dimension with integer values in addition to at least one measure.
Query Fusion
Query Fusion runs a single combined query, replacing multiple individual queries for views that have the same level of detail. This reduces the workload on your database and improves load times. The new cross-database join feature is a fantastic addition that now supports the ability to create an inner-join between databases will improve the performance of the workbook by only querying for the required rows. This new addition also adds support for row level calculations that use data from both databases.
Granularity
Refers to the level of detail in the model or the decision-making process
Binned Data
Similar to a Histogram, shows frequency of numbers between a range. Four field Tableau would check: Min: The field's minimum value. Max: The field's maximum value. Diff: The difference between the field's minimum and maximum values. CntD: The number of distinct values (rows) in the data.
Drag & Drop Analytics
Tired of searching menus for analytics features? Try our new analytics pane where you can easily add analytics, such as a reference line, to a viz by just dragging it onto the canvas. You may also discover something you didn't know existed.
Ad-hoc Analysis
Want to enter simple calcs quickly? No problem, with type-in pills you can enter expressions directly in the shelves.
Device Preview/Device Designer
When in the dashboard layout, there is now a device preview button. This allows the developer to preview the layout over many different device types. When the user selects fit all, the dashboard will automatically scale to fit inside whatever device is currently selected in the device preview pane.
Reference Lines
You can use a reference line to mark a specific value or area on an axis in your view. Or you can add a reference line to any continuous axis. Reference lines are straight lines that originate from a constant or computed value on an axis. There are many different options for reference lines and you can apply more than one reference line to the axis.
Pareto Chart
a bar graph whose bars are drawn in decreasing order of frequency or relative frequency
Cluster Analysis
a technique used to divide an information set into mutually exclusive groups such that the members of each group are as close together as possible to one another and the different groups are as far apart as possible The clustering function uses k-means to cluster the data set based upon the measures and dimensions that are dragged into the new Cluster Variables card. You can specify the number of clusters that you wish to have or you can leave the Number of Clusters field blank and Tableau default to the ideal amount.
Data Source Filters
applying Data source filters won't change to the volume data and size of the extract. Instead data source filters applies the filters to the background query when we use any of the dimensions or measures in the visualizations.
Extract Filters
extract filters are used to filter out the data while creating the extract.
Seasonality
regularly occurring conditions that vary with the time of year So if you aggregate by months, Tableau will look for a 12-month cycle; if you aggregate by quarters, Tableau will search for a four-quarter cycle; and if you aggregate by days, Tableau will search for weekly seasonality. **if there is a six-month cycle in your monthly time series, Tableau will probably find a 12-month pattern that contains two similar sub-patterns. However, if there is a seven-month cycle in your monthly time series, Tableau will probably find no cycle at all.