Replacing null freight amounts with zero to keep per-order averages correct

PL-300 By islever Editorial Last updated Sep 25, 2026

Profile and clean the data

Short answer

D Replacing null Freight Amount with 0 counts no-freight orders as zero cost without losing any order rows.

Question

You use Power Query Editor to preview a query that contains sales order data in the following columns: • Tax Amount • Sales Order ID • Freight Amount • Subtotal Amount • Total Item Quantity The Sales Order ID column uniquely identifies each sales order. The Subtotal Amount and Total Item Quantity columns are always populated, but the Tax Amount and Freight Amount columns are sometimes null when an order has no associated amount. You need to query the data to identify the following metrics by month: • The average item quantity per order • The average freight amount per order • The maximum item quantity per order How should you modify the query?

In the Total Item Quantity column, replace the null values with 0.
In the Tax Amount column, remove rows that contain null values.
In the Freight Amount column, remove rows that contain null values.
In the Freight Amount column, replace the null values with 0. Correct Answer

Key Takeaways

A null freight means the order carried no freight cost, which is a true zero for averaging purposes — replacing nulls with 0 keeps every order in the per-order average, while removing rows would silently drop orders from all three metrics.

Sales order data is aggregated by month to produce average item quantity per order, average freight per order, and maximum item quantity per order, while Tax and Freight columns are sometimes null for orders without those amounts.

Common mistake: Removing null rows in Freight or Tax — deleting rows discards the Sales Order ID, quantities, and subtotals of those orders, corrupting the quantity averages and maximums that depend on them.

Expert Analysis

Why the Answer Is Correct

The metrics are per-order aggregates over all orders in a month. A null in Freight Amount signifies the order has no associated freight — semantically zero — so replacing those nulls with 0 (D) lets the average freight per order include every order with its true zero cost. The quantity columns are always populated, so quantity metrics remain exact, and no order is lost.

Why the Other Options Are Wrong

Replacing nulls in Total Item Quantity (A) is pointless — the scenario states that column is always populated, so there are no nulls to replace. Removing rows with null Tax Amount (B) would delete entire orders (with their quantities and freight) from every monthly metric merely because tax was absent, distorting all three results. Removing rows with null Freight (C) likewise drops valid orders from the average quantity and maximum quantity calculations — the row-level destruction is the fatal flaw both share.

Community Comment Notes

The most-endorsed comment states the essentials: removal is never the solution and quantity is always present, so nulls belong in Freight replaced with 0. A thoughtful reply questions whether zeros distort the freight average, but an order with no freight genuinely contributes zero freight, making the replacement semantically correct.

Official Reference

https://learn.microsoft.com/en-us/power-query/replace-values

This link opens the official vendor documentation in a new tab.

Community Votes

100%

100% of anonymous learners picked answer D. Votes are pick records left by other test-takers — they are not the verified answer.

Discussion 9 contributions

Compiled from public community threads and reader submissions, lightly edited for clarity. Handles and vote tallies are shown as recorded, and comments reflect the views of individual contributors.

From public community threads 9

rajukg 👍 11

D is the correct answer. Removing rows is not the solution. Item Quantity is always present. Replace Freight Amount with 0 if it is null
GustavoFring 👍 6

Won't replacing null values with zero bring down the average freight amount? That wouldn't be an accurate average of the freight amounts when rows with no data are still included. Unless the client would be okay with that,
Florinuca 👍 4

From my point of view, no option is correct! Why? Because the "freight Amount" column is the problem. If this column has no values for all rows, so it can have "null" values, it is not recommended to create a visualization where we use the AVERAGE operation for this column (the sum will always be ok, but the number by which it is divided is not correct, taking into account null values it will be higher and we will never obtain a correct average ). A similar question was in the documentation for the preparation of this exam. Also, we can't remove the rows that contain null values based on "Freight Amount" column, because the deleted rows will contain information for the other columns that are used in the analysis and we won't get real and correct results in their analysis.
0e18c76 👍 2

I agree with the response. However, If replacing null values by zero for freight amounts is correct, I suppose that replacing null values by zero for Tax amount would be correct, as well. To have a more complete response, why not considering also this option?
rcaliandro 👍 2 Answered D

Replace the nulls with 0's in the Freight Amount column

Show 4 more comments

YaakovShlomo 👍 2 Answered D

Need to get rid of nulls so we can aggregate
jaume 👍 1 Answered D

A. is "...always populated...:" so no need o replace any null value B. removing rows with null values would also remove information from other columns that are required for the report C. similar to previous, we cannot remove any column without losing needed information D. to calculate averages, we need to replace ull values with 0
99fafba 👍 1

Svp pourquoi D serait vrai et pas A?
noone420 👍 3 Answered D

D is the answer

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