Mean Median Mode Range Notes

Mean/Average

​The average of a group of data points. The “Balance Point”

To find:

1.) Add up all the data points.

2.) Divide by the number of data points.

Example: Data Set: {2 , 3 , 2 , 1, 2}

( 2 + 3 + 2 + 1 + 2 )/ 5 = 10 / 5 = 2

Median

The middle number when data is arranged in ascending order.

To find:

1.) Order points from smallest to greatest

2.) Find the middle number by crossing off a number in the front and then the back until you are left with one (sometimes two) numbers
*If you are left with two numbers in the middle, take the mean of those two numbers

Example: Data Set: {2 , 3 , 2 , 1, 2} Example Data Set: { 2, 3, 1, 3, 2, 4}
1 , 2, 2, 2, 3 median equals 2 1, 2 , 2, 3, 3, 4 median equals ( (2+3)/2) )= 2.5

Range

The difference between the greatest number in the data set and the least number in the data set.

To find:

1.) Subtract the largest number and the smallest number in the data set


Example: Data Set: {2 , 3 , 2 , 1, 2}
3 - 1 = 2

Mode

The number that occurs the most in a data set.

To find:

1.) Find the number that shows up the most


Example: Data Set: {2 , 3 , 2 , 1, 2}
1 , 2 , 2, 2, 3

The mode is 2

Find the mean, median, mode and range for the following data set. 1, 3, 5, 9, 8, 5, 8, 6

Mean:
Median:
Mode:
Range: