GRE Math : Data Analysis
Study concepts, example questions & explanations for GRE Math
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Example Questions
Example Question #12 : Arithmetic Mean
Quantitative Comparison
The average weight of the 7 cats at the veterinarian's office is 8 pounds. The average weight of the 12 dogs at the vet is 16 pounds.
Quantity A: The average weight of all of the animals
Quantity B: The average weight of the cats plus the average weight of the dogs
Quantity A is greater.
The relationship cannot be determined from the information given.
The two quantities are equal.
Quantity B is greater.
Quantity B is greater.
Quantity B has fewer calculations so let's look at that first. We just need to add up the two averages, so Quantity B = 8 + 16 = 24.
To calculate Quantity A, we need the formula for average = total sum / total number of animals = (7 * 8 + 12 * 16) / (7 + 12) = 248/19 = 13.05.
13.05 is less than 24, so Quantity B is greater.
Example Question #112 : Data Analysis
Alice scored an 87, 85, 90, and 73 on her first four tests of the year. If she wants to have an 87% average in the class, what must she score on her 5th test, assuming the five tests are weighted equally?
96
93
100
90
87
100
(87 + 85 + 90 + 73 + x) / 5 = 87
335 + x = 435
x = 100
Example Question #22 : Statistics
Lucy averages 83% on her first 5 tests. What must she score on her sixth test to raise her class average to an 84, assuming all tests are weighted equally?
90
84
85
91
89
89
For the first 5 tests, Sum / 5 = 83, so Sum = 5 * 83 = 415.
Now to solve for the last test, (415 + x) / 6 = 84. Then 415 + x = 504, and x = 89.
Example Question #23 : Statistics
There exists a function f(x) = 3x + 2 for x = 2, 3, 4, 5, and 6. What is the average value of the function?
14
25
6
20
4
14
First we need to find the values of the function: f(2) = 3 * 2 + 2 = 8, f(3) = 11, f(4) = 14, f(5) = 17, and f(6) = 20. Then we can take the average of the five numbers:
average = (8 + 11 + 14 + 17 + 20) / 5 = 14
Example Question #31 : Statistics
What is the arithmetic mean (average) of the following set of numbers:
34, 26, 18, 12, 40
26
12
40
34
18
26
If in a set of numbers, the numbers are: 
To find the average, add up the sum of all the numbers and divide by the number of items present.
Example Question #116 : Data Analysis
What is the average (arithmetic mean) of all multiples of five from 5 to 45 inclusive?
20
28
15
25
24.4
25
All multiples of 5 must first be added.
5 + 10 + 15 + 20 + 25 + 30 + 35 + 40 + 45 = 225
Because we added 9 terms, the product must be divided by 9.
225 / 9 = 25.
25 is the average.
Example Question #31 : Statistics
What is the average of 
Average is the sum of all the terms divided by the number of terms. So:
Example Question #32 : Statistics
If the average test score of three students is 70, which of the following could a fourth student receive such that the average of all four scores is greater than 73 and less than 75?
The sum of the scores of the first three students whose average was 70 is 
If the average needs to be between 73 and 75 then:
Solving for
Only 83 falls in that range.
Example Question #33 : Statistics
Jane had an arithmetic mean of 84 on the first four math tests she took this year. By the time she'd taken six tests, her arithmetic mean was 86. Assuming that 100 is the maximum number of points possible per test, what is the lowest score that Jane could have possibly received on her fifth test?
To achieve an average of 84 on the first four tests, Jane would have to have received a total of 
Example Question #34 : Statistics
Which statement is true assuming that a represents the range, b represents the mean, c represents the median, and d represents the mode.
which sequence is correct for the number set: 8, 3, 11, 12, 3, 4, 6, 15, 1 ?
The answer is 
First organize the number set 1, 3, 3, 4, 6, 8, 11, 12, 15
a = range = 14
b = mean = 7
c = median = 6
d = mode = 3
so the order is mode<median<mean<range
or d < c < b < a.
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