Download Notes Outline: Summation Notation and Mean Absolute Deviation

Algebra ACE
Summation Notation &
Mean Absolute Deviation – MAD
I.
Name: ___________________
Summation Notation

A mathematical representation for ______________ elements of a __________
_________.

Summation Notation is also called ______________ ___________, the after
the capital Greek letter.
It looks like this:

n
To represent the process of adding a set of data elements we write:
where
x
i 1
i
xi
represents a _________ ____________
“index”
i represents its ____________ in that set of data.
“n”
represents the __________ __________ of elements in the data.
The Jones family has 6 members (including Fluffy and Spot), so n = 6. Their heights the
elements of our data set.
Member
Height
Data set is {65, 72, 70, 58, 22, 28}
Mom
Dad
Bobby
Joey
Fluffy
Spot
65”
72”
70”
58”
22”
28”
So, x1 = 64
x2 = 72
x3 = 70
x4 = 58
x5 = 22
x6 = 28
________ or “mu” is our new symbol for mean (average). It is also a Greek letter.
Now our formula for finding the mean looks like this:
Find  for the Jones family heights.
 = _____________ inches.
Write the formula here:
Algebra ACE
II.
Mean Absolute Deviation (MAD)
Mean Absolute Deviation is a way to determine the _____________ or
________________ of a set of data.
When we calculate the MAD, we can use it to give is a general idea of what is considered
“normal” for that particular set of data.
MAD is often preferred by statisticians over its cousin ____________
________________ because it is less affected by ________________.
The formula for Mean Absolute Deviation:
𝑛
MAD =
∑𝑖=1 |𝑥𝑖 −𝜇|
𝑛
Step 1: Find the ______________.
Step 2: ________________ the mean from each element in the data set.
Step 3: Write down the ________________ ___________ for each of those differences.
Step 4: ____________ those numbers.
Step 5: ____________________ that sum by n (the number of elements in the data set)
Complete each step for our set of data. Jones family heights = {65, 72, 70, 58, 22, 28}
Step 1:
Step 2:
Step 3:
Step 4:
Step 5: MAD =
What does the MAD tell us about the heights of the Jones family?
__________________________________________________________________
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