Blog 4: Professor Callahan teaches mean, median, and mode.

Hello, I am Professor Callahan and today I will be teaching you how to calculate mean, median and mode.

First I will teach you the vocabulary then lead you through examples to help you better understand the concepts. 

Vocabulary:

set = a sequence of numbers

mean = The average of numbers in set

median =  When the numbers are laid out in order from least to greatest it is the middle number in the line. 

mode = the number that appears the most in the set

Let's use an example to help you understand how to calculate these three things.

Example One:

Number of pieces of candy each kid in Ms. Callahans class has

2, 5, 12, 7, 5, 9, 1, 7, 7, 6, 4, 7, 8, 12, 8, 4, 2, 5, 12

First, put numbers in order from least to greatest

1, 2, 2, 4, 4, 5, 5, 5, 6, 7, 7, 7, 7, 8, 8, 9, 12,12,12

MEDIAN

Once the numbers are in order, you can calculate the median by counting from the edges of the sequence until you get to the middle number. In this example, the middle number is 7. therefore 7 is the median.

MODE

To find the mode, you count up how many times each number comes up in the set. Whichever one appears the most is the mode.

1= 1 time

2= 2 times

4= 2 times

5= 3 times

6= 1 time

7= 4 times

8= 2 times

9= 1 time

12= 3 times

7 is the mode because it shows up 4 times which is the most in this set.

MEAN

Calculating the mean is simple algebra. It only takes 2 steps.

First you add up all the numbers in the sequence. Next you divide the sum by the number of numbers in the set.

1+2+2+4+4+5+5+5+6+7+7+7+7+8+8+9+12+12+12= 123

123 / 19 = 6.47368421 = MEAN

The mean is approximately 6.47

Example Two:

Average of test scores in Ms. Callahans class

80, 40, 75, 90, 100, 80, 85

First, put numbers in order

40, 75, 80, 80, 85, 90, 100

MEDIAN

Once the numbers are in order, you can calculate the median by counting from the edges of the sequence until you get to the middle number. In this example, the middle number is 80

The median is 80

MODE

40= 1 time

75= 1 time

80= 2 times

85= 1 time

90=1 time

100= 1 time

Mode= 80 because it is repeated the most amount of times

MEAN

Add up all the numbers

40+75+80+85+80+90+100= 550

Divide

550/7 = 78.57

The mean is 78.57