PL-300 Visualize and analyze the data Practice Question
You are a Power BI data analyst for a manufacturing company. You have a report with a scatter chart that plots production cost (X-axis) versus defect rate (Y-axis) for various production lines. You want to enable users to quickly identify production lines that have both high cost and high defect rate. You decide to add a reference line that divides the chart into quadrants. What should you do?
⚠ Common exam trap
The trap here is thinking that a trend line or a single axis line can create quadrants; quadrants require two perpendicular reference lines, one on each axis.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Add a constant line to the X-axis and a constant line to the Y-axis, setting each to the respective average values.
Scatter charts in Power BI allow constant lines on both the X and Y axes. By adding a constant line on each axis at the average values, you create a quadrant view. Points in the upper-right quadrant have both high cost and high defect rate, making them easy to spot. This is the correct approach for quadrant analysis.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Use the 'Analytics' pane to add a 'Median' line on the X-axis only.
Why it's wrong here
Adding only a median line on the X-axis would split the chart vertically but not horizontally, so it would not create four quadrants. You need lines on both axes to form quadrants. Also, the median may not be the desired threshold; average is more common for cost and defect rate.
- ✓
Add a constant line to the X-axis and a constant line to the Y-axis, setting each to the respective average values.
Why this is correct
Scatter charts support constant lines on both the X and Y axes. By adding a constant line on each axis at the average cost and average defect rate, you create a quadrant view. Points in the upper-right quadrant represent production lines with above-average cost and above-average defect rate, exactly what you need.
- ✗
Create a calculated column that categorizes each production line into a quadrant and use it as a legend.
Why it's wrong here
While this would categorize points, it would not add reference lines to the chart. The user asked for a reference line to divide the chart into quadrants, which is a visual aid. A calculated column used as a legend would change the color of points but not provide the visual quadrant lines.
- ✗
Add a trend line and set it to 'Linear' to show the relationship between cost and defect rate.
Why it's wrong here
A trend line shows the correlation between the two variables but does not divide the chart into quadrants. It would not help users identify points that are above average on both axes simultaneously. The requirement is for a quadrant analysis, not a trend.
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Last reviewed September 2026 · checked against the official Microsoft exam blueprint
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