Algebra II : Median

Study concepts, example questions & explanations for Algebra II

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Example Questions

Example Question #71 : Median

Determine the median:  \(\displaystyle [-3,9,-5,0,-33,-77,23]\)

Possible Answers:

\(\displaystyle -3\)

\(\displaystyle 100\)

\(\displaystyle 0\)

\(\displaystyle 50\)

\(\displaystyle -\frac{86}{7}\)

Correct answer:

\(\displaystyle -3\)

Explanation:

Organize the data set from least to greatest.

\(\displaystyle [-3,9,-5,0,-33,-77,23]\rightarrow[-77,-33,-5,-3,0,9,23]\)

The median is the central number in an odd number of numbers provided.

The answer is:  \(\displaystyle -3\)

Example Question #72 : Median

Determine the median:  \(\displaystyle [-9,30,5,-7]\)

Possible Answers:

\(\displaystyle -8\)

\(\displaystyle -1\)

\(\displaystyle 1\)

\(\displaystyle \frac{35}{2}\)

\(\displaystyle \textup{There is no median.}\)

Correct answer:

\(\displaystyle -1\)

Explanation:

The median is the center number of a data set.  However, since we have an even number of numbers given, we will need to arrange the set from least to greatest, and average the central two numbers.

Reorganize the numbers from least to greatest.

\(\displaystyle [-9,30,5,-7] \rightarrow [ -9,-7,5,30]\)

Average the two center numbers in the data set.

\(\displaystyle \frac{-7+5}{2} = \frac{-2}{2}=-1\)

The answer is:  \(\displaystyle -1\)

Example Question #73 : Median

Determine the median:  \(\displaystyle [ -6,33,-8,50]\)

Possible Answers:

\(\displaystyle \frac{27}{2}\)

\(\displaystyle \frac{41}{2}\)

\(\displaystyle \frac{25}{2}\)

\(\displaystyle -\frac{41}{2}\)

\(\displaystyle \textup{There is no median.}\)

Correct answer:

\(\displaystyle \frac{27}{2}\)

Explanation:

Reorganize the data set in chronological order from least to greatest.

\(\displaystyle [ -6,33,-8,50] \rightarrow [-8,-6,33,50]\)

The median of an even set of numbers is the average of the central two numbers of the chronological ordered data set.

Average the two numbers.

\(\displaystyle \frac{-6+33}{2} = \frac{27}{2}\)

The answer is:  \(\displaystyle \frac{27}{2}\)

Example Question #74 : Median

Determine the median of the numbers:  \(\displaystyle [2,66,84,95]\)

Possible Answers:

\(\displaystyle \textup{There is no median.}\)

\(\displaystyle \frac{97}{2}\)

\(\displaystyle 75\)

\(\displaystyle \frac{247}{2}\)

\(\displaystyle \frac{147}{2}\)

Correct answer:

\(\displaystyle 75\)

Explanation:

The median of an even set of data is the average of the two central numbers of a chronologically ordered data set from least to greatest.

The set is already in order from least to greatest.  

Average the two center numbers.

\(\displaystyle \frac{66+84}{2} = 75\)

The answer is:  \(\displaystyle 75\)

Example Question #75 : Median

Determine the median:  \(\displaystyle [-9,3,-9,18,-9,8]\)

Possible Answers:

\(\displaystyle 2\)

\(\displaystyle -9\)

\(\displaystyle -3\)

\(\displaystyle -18\)

\(\displaystyle \frac{9}{2}\)

Correct answer:

\(\displaystyle -3\)

Explanation:

The median of an even numbered set of numbers is the average of the center two numbers of a data set from least to greatest.

Rearrange the numbers from least to greatest.

\(\displaystyle [-9,3,-9,18,-9,8] \rightarrow [ -9,-9,-9,3,8,18]\)

Average the center two numbers.

\(\displaystyle \frac{-9+3}{2} = \frac{-6}{2}\)

The answer is:  \(\displaystyle -3\)

Example Question #306 : Basic Statistics

Determine the median:  \(\displaystyle [-9,-9,-8,13,27,61]\)

Possible Answers:

\(\displaystyle \textup{There is no median.}\)

\(\displaystyle \frac{25}{3}\)

\(\displaystyle \frac{21}{2}\)

\(\displaystyle \frac{5}{2}\)

\(\displaystyle \frac{25}{2}\)

Correct answer:

\(\displaystyle \frac{5}{2}\)

Explanation:

The median of an even numbered data set is the average of the central two numbers in a chronologically ordered data set from least to greatest.

The set of numbers are already from least to greatest.

Average the two center numbers.

\(\displaystyle \frac{-8+13}{2} = \frac{5}{2}\)

The median is:  \(\displaystyle \frac{5}{2}\)

Example Question #307 : Basic Statistics

Determine the median of the numbers:  \(\displaystyle [-5,11,-9,-15]\)

Possible Answers:

\(\displaystyle 10\)

\(\displaystyle 1\)

\(\displaystyle -7\)

\(\displaystyle \textup{The median does not exist.}\)

\(\displaystyle 7\)

Correct answer:

\(\displaystyle -7\)

Explanation:

Reorganize all the numbers from least to greatest.

\(\displaystyle [-5,11,-9,-15]\rightarrow [-15,-9,-5,11]\)

The median for an even amount of numbers in the data set is the average of the two central numbers.

Average the two numbers.

\(\displaystyle \frac{-9+(-5)}{2} = \frac{-14}{2} = -7\)

The median is:  \(\displaystyle -7\)

Example Question #281 : Data Properties

Most chess tournaments use a rating system called Elo, which is named after a physics professor named Arpad Elo who developed the rating system. The 2014 Sinquefield Cup was a tournament in which the elite chess players of the world competed. Below is a list of their Elo ratings.

 

Sinquefield

Find the median Elo rating of the players participating in the 2014 Sinquefield Cup.

Possible Answers:

\(\displaystyle 4.5\)

\(\displaystyle 2794\)

\(\displaystyle 2772\)

\(\displaystyle 2768\)

\(\displaystyle 2802\)

Correct answer:

\(\displaystyle 2794\)

Explanation:

Step 1:

To make this problem easier to solve, let's list out the Elo ratings from least to greatest.

 \(\displaystyle 2768, 2772, 2787, 2801, 2805, 2877\)

Step 2:

Because there are an even amount of players, there will be two middle terms. We must take the average of the two middle terms in order to get an accurate median value.

 \(\displaystyle (2787+2801) / 2\)

\(\displaystyle 2794\) 

Solution: \(\displaystyle 2794\)

Example Question #76 : Median

Find the median of the data. 

\(\displaystyle \{1,85,3,8,54,21,46,3,154\}\)

Possible Answers:

\(\displaystyle 41.67\)

\(\displaystyle 8\)

\(\displaystyle 21\)

\(\displaystyle 46\)

\(\displaystyle 3\)

Correct answer:

\(\displaystyle 21\)

Explanation:

The median in the number in the middle of the data set.

Arrange the data in numerical order.

\(\displaystyle \{1,85,3,8,54,21,46,3,154\}\rightarrow\)  \(\displaystyle \{1,3,3,8,{\color{Red} 21},46,54,85,154\}\).

Therefore, the median is 21.

Example Question #283 : Data Properties

Give the median of the following data:

 

\(\displaystyle 12, 43, 50, 83, 59, 23, 20, 42, 95, 59, 20\)

Possible Answers:

\(\displaystyle 59\) and \(\displaystyle 20\)

\(\displaystyle 506\)

\(\displaystyle 43\)

\(\displaystyle 46\)

Correct answer:

\(\displaystyle 43\)

Explanation:

The correct answer is \(\displaystyle 43\). It is regarded as the middle value, or the average of the two middle values of a data set. The first step in finding the median is ordering the data from least to greatest. 

 

\(\displaystyle 12, 20, 20, 23, 42, 43, 50, 59, 59, 83, 95\)

 

From here, find the middle value. In this case, that is the \(\displaystyle 6\)th value, \(\displaystyle 43\)

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