**GMAT Focus Edition: Table Analysis – Sorting & Conditional Filtering**

GMAT Focus Edition: Table Analysis – Sorting & Conditional Filtering

Data Insights Study Guide

What This Is

Table Analysis questions present a data table (often 5–10 rows × 4–6 columns) and ask you to sort, filter, or evaluate statements based on the data. The GMAT tests your ability to quickly extract insights from structured data—mirroring real-world business scenarios where decisions hinge on interpreting spreadsheets, financial reports, or survey results. These questions appear in the Data Insights section and account for ~20% of your DI score. A single question can include 3–4 statements, each requiring you to sort the table differently or apply conditional logic (e.g., "If X > Y, how many rows satisfy Z?").

Example GMAT-Style Question:
A table lists 8 employees with columns for Department, Salary, Tenure (years), and Performance Rating (1–5). Statement: "After sorting by Salary in descending order, the median Tenure of the top 3 earners is greater than the median Tenure of all employees." Task: Evaluate whether the statement is true, false, or cannot be determined.

Key Concepts & Techniques

1. Primary vs. Secondary Sorting
2. What it is: Sorting first by one column (primary), then by another (secondary) to break ties.

3. When to use: When a statement mentions two criteria (e.g., "Sort by Salary, then by Tenure"). Always sort the primary column first, then the secondary.

4. Conditional Filtering (IF-THEN Logic)

5. What it is: Applying a condition (e.g., "IF Performance Rating ≥ 4") to subset the data before analyzing.

6. When to use: When a statement includes phrases like "among employees with X," "if Y is true," or "for rows where Z > 10."

7. Median vs. Mean vs. Mode

8. What it is:
   • Median: Middle value when data is sorted (for even counts, average the two middle values).
   • Mean: Sum of values ÷ count.
   • Mode: Most frequent value.

9. When to use: Statements often ask for medians (less sensitive to outliers) or means (requires calculation). Never assume—check the question.

10. Top/Bottom N Rows

11. What it is: Isolating the first N or last N rows after sorting.

12. When to use: Phrases like "top 3 earners," "bottom 25%," or "the 5th-highest value."

13. Count vs. Proportion

14. What it is: Counting rows that meet a condition vs. calculating a percentage.

15. When to use: "How many rows satisfy X?" (count) vs. "What % of rows satisfy X?" (proportion).

16. Cross-Column Comparisons

17. What it is: Comparing values across columns (e.g., "Salary > Tenure × 1000").

18. When to use: Statements like "For how many rows is Column A > Column B?" Requires row-by-row evaluation.

19. Cannot Be Determined (CBD)

20. What it is: Recognizing when data is missing or ambiguous (e.g., ties in median calculations, insufficient rows).
21. When to use: If a statement requires assumptions (e.g., "the average of X" when X has missing values) or ties (e.g., "the 3rd-highest value" when there are duplicates).

Step-by-Step Strategy

Follow this process for EVERY Table Analysis question:

1. Read the Question First
2. Identify what you’re being asked (e.g., "Is the median X > Y?" or "How many rows satisfy Z?").

3. Note all conditions (e.g., "IF Department = Marketing").

4. Sort the Table (If Required)

5. Apply the primary sort (e.g., "Sort by Salary descending").

6. Apply the secondary sort (if needed) to break ties (e.g., "then by Tenure ascending").

7. Apply Conditional Filters (If Any)

8. Subset the data before analyzing (e.g., "Only rows where Performance Rating ≥ 4").

9. Highlight or mentally mark the filtered rows to avoid mistakes.

10. Extract the Required Statistic

11. For counts/proportions: Count rows meeting the condition.
12. For medians/means: Sort the relevant column, then calculate.

13. For cross-column comparisons: Evaluate each row individually.

14. Evaluate Each Statement

15. For True/False/CBD questions: Compare your result to the statement.

16. For multiple-choice questions: Match your answer to the options.

17. Double-Check for Traps

18. Ties: If sorting for "top N," check for duplicate values.
19. Missing data: If a column has blanks, the statement may be CBD.
20. Units: Ensure all values are in the same units (e.g., $ vs. $000).

Fully Worked Example

Table: Employee Data (8 Rows)

Statement: "After sorting by Salary in descending order, the median Tenure of the top 3 earners is greater than the median Tenure of all employees."

Step-by-Step Solution:

1. Read the Question:
2. We need to compare median Tenure of top 3 earners vs. median Tenure of all employees.

3. Sorting required: Salary descending.

4. Sort the Table by Salary (Descending):

1. Isolate Top 3 Earners:
2. Employees H, B, E → Tenures: 7, 5, 6.

3. Median of top 3: Sort tenures → 5, 6, 7 → Median = 6.

4. Calculate Median Tenure of All Employees:

5. All tenures: 3, 5, 2, 4, 6, 5, 3, 7 → Sort → 2, 3, 3, 4, 5, 5, 6, 7.

6. Median of 8 values: Average of 4th and 5th → (4 + 5)/2 = 4.5.

7. Compare:

8. Top 3 median = 6.
9. All employees median = 4.5.
10. 6 > 4.5 → Statement is TRUE.

Common Mistakes

1. Mistake: Ignoring secondary sorts.
2. Why it happens: Students sort by the primary column but forget to break ties (e.g., two employees with $92K salary).

3. Correct approach: Always check if a secondary sort is implied (e.g., "then by Tenure").

4. Mistake: Misapplying conditional filters.

5. Why it happens: Students filter after calculating (e.g., find median of all rows, then filter).

6. Correct approach: Filter first, then calculate (e.g., "IF Performance Rating ≥ 4, then find median Tenure").

7. Mistake: Confusing median and mean.

8. Why it happens: Students calculate the mean when the question asks for the median (or vice versa).

9. Correct approach: Circle "median" or "mean" in the question to avoid autopilot errors.

10. Mistake: Counting rows incorrectly.

11. Why it happens: Students miscount when filtering (e.g., "top 3" includes ties).

12. Correct approach: Write down the filtered rows to avoid off-by-one errors.

13. Mistake: Overlooking "Cannot Be Determined."

14. Why it happens: Students assume data is complete (e.g., no missing values, no ties).
15. Correct approach: Check for:
    • Missing data (blanks in columns).
    • Ties in median calculations (e.g., even number of rows).
    • Ambiguous conditions (e.g., "the 3rd-highest value" when there are duplicates).

GMAT Traps & Timing

1. Trap: Hidden Secondary Sorts
2. What it is: The question implies a secondary sort (e.g., "the highest-paid employee in Marketing").

3. How to avoid: Always ask: "What if there’s a tie?" Sort by the secondary column to break it.

4. Trap: Proportion vs. Count

5. What it is: The question asks for a percentage but the table only gives counts.

6. How to avoid: Calculate the total rows first, then divide.

7. Trap: Units Mismatch

8. What it is: Salary is in $000, but the question uses $ (e.g., "Salary > 80" vs. "Salary > 80,000").

9. How to avoid: Check the table header for units before comparing.

10. Timing:

11. Spend 2–3 minutes per question (including reading, sorting, and evaluating all statements).
12. Flag and move on if a statement takes >45 seconds—guess and return later.

Quick Practice

Question:
A table lists 6 products with columns for Price ($), Units Sold, and Region (North/South).

Statement: "After sorting by Units Sold in descending order, the median Price of the top 3 products is greater than the median Price of all products in the South region."

Answer: False
Explanation: - Sort by Units Sold descending → P4 (10), P6 (12), P2 (15), P1 (20), P3 (25), P5 (30).
- Top 3 Prices: 10, 12, 15 → Median = 12.
- South region Prices: 15, 10, 12 → Sorted: 10, 12, 15 → Median = 12.
- 12 is not greater than 12.

Last-Minute Cram Sheet

1. Always sort/filter BEFORE calculating—never the reverse.
2. Median of even counts = average of middle two values.
3. Top N rows = first N after sorting (include ties if not specified).
4. "Cannot be determined" if:
5. Data is missing (blanks).
6. Ties exist in median/rank calculations.
7. Conditions are ambiguous (e.g., "the 3rd-highest" with duplicates).
8. Secondary sorts break ties—check for them in every question.
9. Proportion = (Count ÷ Total Rows) × 100—don’t forget to divide!
10. Cross-column comparisons require row-by-row evaluation.
11. Units matter—check table headers for $ vs. $000, etc.
12. Flag and move on if a statement takes >45 seconds.
13. Common wrong answers:
    • Using mean instead of median (or vice versa).
    • Ignoring conditional filters.
    • Miscounting rows (off-by-one errors).