GMAT Math : Descriptive Statistics

Study concepts, example questions & explanations for GMAT Math

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Example Questions

Example Question #463 : Arithmetic

Find the range of the following set of numbers:

Possible Answers:

Correct answer:

Explanation:

To find range, subtract the smallest number from the largest number. Thus,

Example Question #11 : Descriptive Statistics

Find the range of the following set of numbers.

1,1,2,7,8,10,11

Possible Answers:

Correct answer:

Explanation:

To find the range, you m ust subtract the smallest number from the largest. Thus,

Example Question #465 : Arithmetic

Find the range of the following data set:

Possible Answers:

Correct answer:

Explanation:

Find the range of the following data set:

Range is as simple as finding the diffference between the largest and smallest terms in a set. So, let's find our largest and smallest terms.

Largest: 989

Smallest: 2

Next, let's calculate the range:

So our answer should be 987

Example Question #14 : Descriptive Statistics

.

Give the midrange of the set .

Possible Answers:

Correct answer:

Explanation:

The midrange of a set is the arithmetic mean of the greatest and least values, which here are  and . This makes the midrange .

Example Question #466 : Arithmetic

A large group of students is given a standardized test. The following information is given about the scores:

Mean: 73.8

Standard deviation: 6.3

Median: 71

25th percentile: 61

75th percentile: 86

Highest score: 100

Lowest score: 12

What is the interquartile range of the tests?

Possible Answers:

More information about the scores is needed.

Correct answer:

Explanation:

The interquartile range of a data set is the difference between the 75th and 25th percentiles:

All other given information is extraneous to the problem.

Example Question #1 : Arithmetic Mean

Salaries for employees at ABC Company: 1 employee makes $25,000 per year, 4 employees make $40,000 per year, 2 employees make $50,000 per year and 5 employees make $75,000 per year.

What is the average (arithmetic mean) salary for the employees at ABC Company?

Possible Answers:

\dpi{100} \small \$ 53,500

\dpi{100} \small \$ 48,640

\dpi{100} \small \$ 46,250

\dpi{100} \small \$ 55,000

\dpi{100} \small \$ 58,000

Correct answer:

\dpi{100} \small \$ 55,000

Explanation:

The average is found by calculating the total payroll and then dividing by the total number of employees. \frac{(1\cdot 25,000)+(4\cdot 40,000)+(2\cdot 50,000)+(5\cdot 75,000)}{1+4+2+5}

 


\frac{25,000+160,000+100,000+375,000}{12} = \frac{660,000}{12}= $55,000

Example Question #2 : Arithmetic Mean

A bowler had an average (arithmetic mean) score of 215 on the first 5 games she bowled. What must she bowl on the 6th game to average 220 overall?

Possible Answers:

\dpi{100} \small 145

\dpi{100} \small 225

\dpi{100} \small 25

\dpi{100} \small 258

\dpi{100} \small 245

Correct answer:

\dpi{100} \small 245

Explanation:

For the first 5 games the bowler has averaged 215. The equation to calculate the answer is

\frac{(215\cdot 5)+x}{6}=220

where \dpi{100} \small x is the score for the sixth game. Next, to solve for the score for the 6th game \dpi{100} \small (x) multiply both sides by 6:

(215\cdot 5)+x =1,320

which simplifies to:

1,075+x =1,320

After subtracting 1,075 from each side we reach the answer:

x =1,320 - 1, 075 = 245

Example Question #3 : Arithmetic Mean

Ashley averaged a score of 87 on her first 5 tests. She scored a 93 on her 6th test. What is her average test score, assuming all 6 tests are weighted equally?

Possible Answers:

\dpi{100} \small 92

\dpi{100} \small 90

\dpi{100} \small 87

\dpi{100} \small 91

\dpi{100} \small 88

Correct answer:

\dpi{100} \small 88

Explanation:

We can't just average 87 and 93! This will give the wrong answer! The average formula is \dpi{100} \small average = \frac{sum}{number\ of\ terms}.

For the first 5 tests, \dpi{100} \small 87=\frac{sum}{5}. Then \dpi{100} \small sum=87\times 5=435.

Now combine that with the 6th test to find the overall average.

\dpi{100} \small average = \frac{435+93}{6}=88

Example Question #1 : Arithmetic Mean

Sabrina made $3,000 a month for three months, $4,000 the next month, and $5,200 a month for the following two months. What was her average monthly income for the 6 month period?

Possible Answers:

\dpi{100} \small \$ 4200

\dpi{100} \small \$ 4500

\dpi{100} \small \$ 4950

\dpi{100} \small \$ 3400

\dpi{100} \small \$ 3900

Correct answer:

\dpi{100} \small \$ 3900

Explanation:

\dpi{100} \small average = \frac{3\times 3000 + 4000 + 2\times 5200}{6} = \$ 3900

Example Question #2021 : Problem Solving Questions

Luke counts the number of gummy bears he eats every day for 1 week: {39, 18, 24, 51, 40, 15, 23}. On average, how many gummy bears does Luke eat each day?

Possible Answers:

\dpi{100} \small 27

\dpi{100} \small 25

\dpi{100} \small 37

\dpi{100} \small 30

\dpi{100} \small 41

Correct answer:

\dpi{100} \small 30

Explanation:

average = \frac{39+18+24+51+40+15+23}{7} = 30

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