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5 votes
5 votes
Suppose a set of scores in College Mathematics are 5, 15, 25, 30, 3. Which of the following is true?

a.
the mean is equal to the median


b.
the mean is less than the median


c.
the mean is greater than the median


d.
the mode is 15

User Cebjyre
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1 Answer

9 votes
9 votes

Answer: c. the mean is greater than the median

Step-by-step explanation:

To find out the correct answer, we first must know the true meanings and the method of calculation of the terms, "mean", "mode" and "median".

Mean: The mean is a type of average. It is the sum of all the values in a set of data, such as numbers of measurements, divided by the numbers of values on the list.

Formula for finding mean-


\bar{x} = (\sum x)/(n) where,
\bar{x}= sample mean

\sum x = sum of each value in sample

n = number of values in the sample

Example: in {6, 3, 9, 6, 6, 5, 9, 3} the mean is 5.875 (6+3+9+6+6+5+9+3/8).

Mode: The mode is the number which appears most often in a set of numbers.
Example: in {6, 3, 9, 6, 6, 5, 9, 3} the Mode is 6.


Median: The median is the "middle" of a sorted list of numbers in ascending order (small to big). To find the Median, place the numbers in value order and find the middle.
Example: in {6, 3, 9, 6, 6, 5, 9, 3} the median is 6. (in 3,3,5,6,6,9,9, the middle number is 6 )

HOWEVER,

with an even amount of numbers things are slightly different.
In that case we find the middle pair of numbers, and then find the value that is half way between them. This is easily done by adding them together and dividing by two. (basically averaging the middle two numbers incase there is an even set of numbers)
Example: 3, 13, 7, 5, 21, 23, 23, 40, 23, 14, 12, 56, 23, 29

When we put those numbers in order we have:

3, 5, 7, 12, 13, 14, 21, 23, 23, 23, 23, 29, 40, 56

There are now fourteen numbers and so we don't have just one middle number, we have a pair of middle numbers.

3, 5, 7, 12, 13, 14, 21, 23, 23, 23, 23, 29, 40, 56

In this example the middle numbers are 21 and 23.

To find the value halfway between them, add them together and divide by 2: 21 + 23 = 44, then 44 ÷ 2 = 22

So the Median in this example is 22.
(Note that 22 was not in the list of numbers ... but that is OK because half the numbers in the list are less, and half the numbers are greater.)

Now that you understand the terms clearly, let's find out the mean, mode and median from your given set of numbers.
5, 15, 25, 30, 3

Mean: (5+15+25+30+3)/5 is, 15.6
Mode: None since none of the numbers repeated more than once.
Median: 3,5,15,25,30 , so the middle number is 15 .

Since there is no mode, option d. can never be the answer. And clearly, 15.6 is greater than 15 so the answer should be c. the mean is greater than the median.

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User Hiroyukik
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