Mean Median and Range Obj 5 b Central

Mean, Median, and Range Obj. 5 b

Central Tendency When you have a “set of data” (or numbers), there are 2 different ways you can find the center of the data. 1) 2) Mean Median Let’s look at these 2 different ways to find the center using the following… Set of Numbers: 2, 3, 1, 1, 0, 1, 2, 4

Mean = Average

Your report card has an average on it. � The � 2 Mean is the average. simple steps will give you the mean of a set of numbers. Step 1 Step 2 Add the numbers. Divide by the # of items in the dataset. Mean = Average

Step 1 Step 2 Add the numbers. Divide by the # of items in the dataset. Set of Numbers: 2, 3, 1, 1, 0, 1, 2, 4 Add the numbers: 2 + 3 + 1 + 0 + 1 + 2 + 4 = Divide by total items: 14 ÷ 8 = 1. 75 Mean 14

Median = Middle

What is the Median? � The Median is the middle number. � How do you find the Median? If there is just 1 middle #: your done! ORDER FIND the numbers. the middle #. If there are 2 middle #’s Median = Middle Average the 2 middle numbers.

Example of Median If there is just 1 middle #: your done! ORDER FIND the numbers. the middle #. If there are 2 middle #’s Average the 2 middle numbers. Add the 2 middle numbers Set of Numbers: 2, 3, 1, 1, 0, 1, 2, 4 Arrange in order: 0, 1, 1, 1, 2, 2, 3, 4 1 + 2 = 3 3 ÷ 2 =1. 5 Median Then, Divide by 2

Range = Biggest – Smallest

What is the Range? � The Range is not a form of central tendency, but it is another way to get information from a “set of numbers”. � The range describes the spread of the dataset. � The Range is the difference between the biggest number and the smallest number. Range = Biggest - Smallest

Example of Range = Biggest – Smallest Set of Numbers: 2, 3, 1, 1, 0, 1, 2, 4 Subtract: 4– 0= 4 Range

Remember. . Mean Average = Median = Middle Range = Biggest – Smallest

You Try! Mandy’s math test scores: 90, 85, 80, 70, 90, 65 Determine the following: Mean Median Range _______

Answers! Mandy’s math test scores: 90, 85, 80, 70, 90, 65 65 70 80 85 90 90 Mean Median Range __80___ __82. 5_ __25___ (find average of 80 & 85)

Closure �What did we learn today (key words): Mean = Median = Range = Average _________ ? Middle_________ ? Most _________ ? Biggest – Smallest �Which central tendency requires you to first put the numbers in order? �When Median finding the median, what do you do if there are 2 middle numbers? Average the two middle numbers by adding them together and dividing by 2.