ISEE Upper Level Math : How to find median

Study concepts, example questions & explanations for ISEE Upper Level Math

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Example Questions

Example Question #31 : Data Analysis And Probability

Consider the data set 

\displaystyle \left \{ 24,61, 27, 57, 34, 37, 63, 50, N\right \}.

For what value(s) of \displaystyle N would this set have median \displaystyle 50?

Possible Answers:

Any number greater than or equal to \displaystyle 50

Any number except \displaystyle 50

Any number less than or equal to \displaystyle 50

Any number less than \displaystyle 50

Any number greater than \displaystyle 50

Correct answer:

Any number greater than or equal to \displaystyle 50

Explanation:

Arrange the eight known values from least to greatest.

\displaystyle \left \{ 24, 27, 34, 37, 50, 57,61, 63\right \}

For \displaystyle 50 to be the median of the nine elements, it muct be the fifth-greatest, This happens if \displaystyle N \geq 50.

Example Question #581 : Isee Upper Level (Grades 9 12) Mathematics Achievement

Consider the data set: \displaystyle \left \{ 12, 15, 18, 20, 20, 21, 23, 26, N\right \}

where \displaystyle N is not known.

What are the possible values of the median of this set?

Possible Answers:

\displaystyle 20\textrm{ or }21

\displaystyle 18 \textrm{ or }20

\displaystyle 20

\displaystyle 18, 20,\textrm{ or }21

Correct answer:

\displaystyle 20

Explanation:

The median of this nine-element set is its fifth-highest element. Of the eight known elements, the fourth-highest and fifth-highest elements are both 20. Regardless of the value of \displaystyle N, 20 is the fifth-highest element of the nine.

Example Question #32 : Data Analysis

Examine this stem-and-leaf display for a set of data:

\displaystyle \left.\begin{matrix} 4\\ 5\\ 6\\ 7\\ 8 \end{matrix}\right|\begin{matrix} \textrm{7 9}\; \; \; \; \; \; \; \; \; \; \;\; \; \; \; \; \; \; \; \; \; \; \; \;\\ \textrm{4 4 7 7}\; \; \; \; \; \; \; \; \; \; \;\; \; \; \; \; \; \; \\ \textrm{0 1 2 2 4 5 5 8 8 9}\\ \textrm{3 5 5 8}\; \; \; \; \; \; \; \; \; \; \;\; \; \; \; \; \; \; \\ \textrm{4 7}\; \; \; \; \; \; \; \; \; \; \;\; \; \; \; \; \; \; \; \; \; \; \; \; \end{matrix}

What is the median of this data set?

Possible Answers:

\displaystyle 65

\displaystyle 64

\displaystyle 64.5

\displaystyle 67

Correct answer:

\displaystyle 64.5

Explanation:

The "stem" of this data set represents the tens digits of the data values; the "leaves" represent the units digits. 

There are 22 elements, so the median is the arithmetic mean of the eleventh- and twelfth-highest elements, which are 64 and 65, the middle two "leaves". Their mean is \displaystyle \left (64 + 65 \right )\div 2 = 64.5.

Example Question #11 : How To Find Median

Determine the median of the following seven test scores:

\displaystyle 88, 93, 79, 95, 80, 81, 93

Possible Answers:

\displaystyle 93

\displaystyle 95

\displaystyle 87

\displaystyle 79

\displaystyle 88

Correct answer:

\displaystyle 88

Explanation:

To determine the median of a set of numbers, you first need to order them from least to greatest:

\displaystyle 79, 80, 81, 88, 93, 93, 95

Since there is an odd number of scores, the median is the score that falls exactly in the middle of the new list. Thus, the median is 88.

Example Question #33 : Data Analysis And Probability

Determine the median of the following set of numbers:

\displaystyle 55, 34, 27, 36, 44, 51

Possible Answers:

\displaystyle 28

\displaystyle 36

\displaystyle 44

\displaystyle 40

\displaystyle 41

Correct answer:

\displaystyle 40

Explanation:

To determine the median of a set of numbers, you first need to order them from least to greatest:

\displaystyle 27, 34, 36, 44, 51, 55

Since there is an even amount of numbers, the median is determined by finding the average of the two numbers in the middle - 36 and 44.

\displaystyle 36+44 = 80 \div 2 = 40

 

Thus, the median is 40.

Example Question #12 : How To Find Median

Find the median of the following numbers:

\displaystyle 2,7,14,4,3

Possible Answers:

\displaystyle 6

\displaystyle 4

\displaystyle 7

\displaystyle 5

Correct answer:

\displaystyle 4

Explanation:

The median is the center number when the data points are listed in ascending or descending order. To find the median, reorder the values in numerical order:

\displaystyle 2,3,4,7,14

In this problem, the middle number, or median, is the third number, which is \displaystyle 4.

Example Question #41 : Data Analysis

What is the median of the following set?

\displaystyle \left ( 5.45, 3.12, 5.7,9.86, 14.78, 3.35\right )

Possible Answers:

\displaystyle 5.575

\displaystyle 5.6

\displaystyle 5.45

\displaystyle 5.7

Correct answer:

\displaystyle 5.575

Explanation:

The first step towards solving for the set, \displaystyle \left ( 5.45, 3.12, 5.7,9.86, 14.78, 3.35\right ) is to reorder the numbers from smallest to largest. 

This gives us:

\displaystyle \left ( 3.12,3.35, 5.45, 5.7,9.86, 14.78\right )

The median is equal to middle number in s a set. In since this set has 6 numbers, which is even, the average of the middle two numbers is the mean. The average can be found using the equation below:

\displaystyle \frac{5.45+5.7}{2}

\displaystyle \frac{11.15}{2}

\displaystyle 5.575

Example Question #593 : Isee Upper Level (Grades 9 12) Mathematics Achievement

Find the median of the following data set:

\displaystyle 45,67,12,34,55,88,67,343,49

Possible Answers:

\displaystyle 331

\displaystyle 55

\displaystyle 84

\displaystyle 67

Correct answer:

\displaystyle 55

Explanation:

Find the median of the following data set:

\displaystyle 45,67,12,34,55,88,67,343,49

Begin by putting your numbers in increasing order:

\displaystyle 12,34,45,49,55,67,67,88,343

Next, identify the median by choosing the middle value:

\displaystyle 12,34,45,49,{\color{Green} 55},67,67,88,343

So, our answer is 55

 

Example Question #13 : How To Find Median

Find the median of the following data set:

\displaystyle 5,76,12,34,55,89,76,109,67,33,9

Possible Answers:

\displaystyle 51

\displaystyle 67

\displaystyle 55

\displaystyle 104

Correct answer:

\displaystyle 55

Explanation:

Find the median of the following data set:

\displaystyle 5,76,12,34,55,89,76,109,67,33,9

Let's begin by rearranging our terms from least to greatest:

\displaystyle 5,9,12,33,34,55,67,76,76,89,109

Now, the median will be the middle term:

\displaystyle 5,9,12,33,34,{\color{DarkOrange} 55},67,76,76,89,109

Example Question #595 : Isee Upper Level (Grades 9 12) Mathematics Achievement

Find the median of the following data set:

\displaystyle 34,56,76,12,33,43,98,99,77,93,33

Possible Answers:

\displaystyle 56

\displaystyle 33

\displaystyle 59

\displaystyle 87

Correct answer:

\displaystyle 56

Explanation:

Find the median of the following data set:

\displaystyle 34,56,76,12,33,43,98,99,77,93,33

First, let's put our terms in increasing order:

\displaystyle 12,33,33,34,43,56,76,77,93,98,99

Now, we can find our median simply by choosing the middle term.

\displaystyle 12,33,33,34,43,{\color{Blue} 56},76,77,93,98,99

So, 56 is our median.

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