Easy GRE Data Analysis Exam Questions Practice Questions

Data analysis accounts for approximately 10 to 12 questions on a typical GRE Quantitative Reasoning section. Success on these problems requires a firm grasp of descriptive statistics, basic probability, and the ability to interpret visual data representations like bar graphs and circle charts. By focusing on Easy GRE Data Analysis Exam Questions, you can build the foundational speed and accuracy needed to tackle the more complex data sets appearing later in the exam. This guide provides a structured approach to identifying trends, calculating averages, and understanding the distribution of data points within a set.

Concept Explanation

Data analysis on the GRE is the study of collecting, summarizing, and interpreting data through statistical measures and graphical displays. At its core, this topic tests your ability to extract relevant information from tables and charts while applying basic mathematical operations. The primary concepts include measures of central tendency—mean, median, and mode—and measures of dispersion, such as range and standard deviation. You will also encounter probability theory, which involves calculating the likelihood of specific events occurring. To excel in this area, you should be comfortable with the following:

• Arithmetic Mean: The sum of all values divided by the number of values.
• Median: The middle value in a sorted list of numbers.
• Mode: The value that appears most frequently in a data set.
• Range: The difference between the highest and lowest values in a set.
• Data Interpretation: Reading values directly from histograms, boxplots, and scatterplots.

Building a strong base in these fundamentals is a key part of any comprehensive GRE Prep strategy, as it ensures you do not lose points on straightforward calculation errors.

Solved Examples

1. Calculating the Mean: A student takes five exams and receives scores of 82, 88, 91, 75, and 84. What is the average (arithmetic mean) score?

1. Sum the scores: $82 + 88 + 91 + 75 + 84 = 420$.
2. Count the number of exams: 5.
3. Divide the sum by the count: $\frac{420}{5} = 84$.
4. The mean score is 84.

2. Finding the Median: Find the median of the following set of numbers: {12, 5, 22, 30, 7, 12, 15}.

1. Arrange the numbers in ascending order: {5, 7, 12, 12, 15, 22, 30}.
2. Identify the total number of elements: 7 (an odd number).
3. The median is the middle term, which is the 4th value.
4. The median is 12.

3. Simple Probability: A bag contains 4 red marbles, 6 blue marbles, and 10 green marbles. If one marble is picked at random, what is the probability it is blue?

1. Find the total number of marbles: $4 + 6 + 10 = 20$.
2. Identify the number of favorable outcomes (blue marbles): 6.
3. Set up the probability fraction: $\frac{6}{20}$.
4. Simplify the fraction: $\frac{3}{10}$ or 0.3.

Practice Questions

1. A set of data consists of the integers {4, 8, 12, 16, 20}. If the number 30 is added to the set, by how much does the mean increase? 2. In a group of 10 students, the heights in centimeters are {150, 162, 155, 170, 158, 162, 165, 162, 175, 160}. What is the mode of this data set? 3. A pie chart shows that 25% of a company's budget is spent on Marketing, 40% on Operations, and the remainder on Research and Development (R&D). If the total budget is $200,000, how much is spent on R&D? 4. If the range of a set of five consecutive even integers is $R$, what is the value of $R$? 5. A fair six-sided die is rolled once. What is the probability of rolling a prime number? 6. The following table shows the number of cars sold by a dealership over 4 months:

April

Month	Cars Sold
January	15
February	22
March	18
25

What is the average number of cars sold per month? 7. A set $S$ contains the elements {10, 20, 30, 40, 50}. If each element in the set is increased by 5, what is the new median? 8. In a data set with 9 unique values, the median is 15. If the largest value is increased by 10, what happens to the median? 9. A box contains 50 light bulbs, 4 of which are defective. If a bulb is selected at random, what is the probability that it is NOT defective? 10. What is the arithmetic mean of the first five positive multiples of 7?

Answers & Explanations

1. Answer: 3. The original mean is $\frac{4+8+12+16+20}{5} = \frac{60}{5} = 12$. The new sum is $60 + 30 = 90$ with 6 elements. The new mean is $\frac{90}{6} = 15$. The increase is $15 - 12 = 3$. You can check similar logic in GRE practice questions with explanations. 2. Answer: 162. The mode is the value that appears most frequently. In the set, 162 appears three times, while all other values appear only once. 3. Answer: $70,000. The percentage for R&D is $100\% - (25\% + 40\%) = 35\%$. To find the amount: $0.35 \times 200,000 = 70,000$. 4. Answer: 8. Let the integers be $x, x+2, x+4, x+6, x+8$. The range is the largest minus the smallest: $(x+8) - x = 8$. 5. Answer: 1/2. The prime numbers on a six-sided die are 2, 3, and 5. There are 3 favorable outcomes out of 6 total possibilities: $\frac{3}{6} = \frac{1}{2}$. 6. Answer: 20. Sum the sales: $15 + 22 + 18 + 25 = 80$. Divide by 4 months: $\frac{80}{4} = 20$. 7. Answer: 35. The original median of {10, 20, 30, 40, 50} is 30. If every number increases by 5, the new set is {15, 25, 35, 45, 55}. The new middle value is 35. 8. Answer: It stays the same. Increasing the largest value in a set does not change the middle position of the data, so the median remains 15. For more on statistical properties, view GRE practice questions with answers. 9. Answer: 23/25. There are $50 - 4 = 46$ non-defective bulbs. The probability is $\frac{46}{50}$, which simplifies to $\frac{23}{25}$ or 0.92. 10. Answer: 21. The first five multiples of 7 are 7, 14, 21, 28, and 35. The mean is $\frac{7+14+21+28+35}{5} = \frac{105}{5} = 21$. Since these are in an arithmetic progression, the mean is also the middle term.

Frequently Asked Questions

What is the difference between mean and median on the GRE?

The mean is the average of all numbers, while the median is the middle value when the numbers are sorted. The mean is more sensitive to outliers, whereas the median provides a better sense of the center for skewed data.

How do I calculate the weighted average?

To find a weighted average, multiply each value by its corresponding weight or frequency, sum those products, and then divide by the total sum of the weights. This is common when different categories contribute differently to a final score.

What does standard deviation represent in data analysis?

Standard deviation is a measure of how spread out the numbers in a data set are around the mean. A low standard deviation means the data points are close to the mean, while a high standard deviation indicates they are spread over a wider range.

Can the mode of a data set be more than one number?

Yes, a data set can have more than one mode if multiple values share the highest frequency, which is called bimodal or multimodal. If no value repeats, the set is said to have no mode.

What is the probability of independent events?

For independent events, the probability of both events occurring is the product of their individual probabilities. You can practice these concepts using an adaptive GRE practice test to see how they appear in different contexts.