# MATH

• WELCOME TO MATH!

Today we will learn about median and mean.
Here are some numbers:   5, 3, 4, 8, 5
Please write those numbers in order on your paper from least to greatest.
Now, look at the set of numbers you have written, and tell me which number is in the middle of that set?
If you said 5you are correct!

Your set of numbers should have looked like this: 3, 4, 5, 5, 8
In order to find the one in the middle, you could cross off a number from each end of the set.
So first, I would cross off the 3 and the 8.
Then, I would cross off another number from each end of the set.
So next, I would cross of the 4, and also the 5 which is located next to the 8.
The only number remaining is the 5.
In this set, 5 is the median, because the middle number in a set of data is called the median.

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Now, imagine you have 15 connecting cubes.
I would like you to arrange the cubes into three towers:
A tower of 3 cubes, a tower of 4 cubes, and a tower of 8 cubes.
(You can actually draw these towers on your paper if you like.)
Now Here's the challenge: Please rearrange the cubes so the three towers are equal in height.
How many cubes high is each tower now?
If you answered 5, you are correct!
You just found the mean, or average height of the original three towers.

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First, read the problem regarding Jenna's line plot.
The textbook tells you how to find the median of her data, and
how to find the mean of her data.
Follow exactly the steps laid out for you on page 238.
Good!

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Let's look at problem #1 on p. 239.
It says to list Lynn's data (from the chart) in order.
(Please list every instance of a number when you write them on your paper.)
My list turned out like this:
1, 1, 2, 2, 3, 4, 4, 5, 5
I have a total of nine numbers written. I can cross off one number from each end of the list until I get down to just one number.
In this case, the middle or median number is 3.

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Now let's do problem #2 on page 239.
In order to find the mean of Lynn's data, I need to figure out the average.
This will be fun! :)

First, I need to add up all the numbers from Lynn's data. So look at the list we made (above); adding it looks like this:

1 + 1 + 2 + 2 + 3 + 4 + 4 + 5 + 5 = ______

The sum of the numbers is 27.
Now I need to divide the sum of the numbers by the actual number of items in the set.
Go back and count how many numbers you see in that addition sentence.
There are a total of nine items listed.
Again, the sum of the numbers is 27. The total items in the set is 9.
I must divide 27 by 9, OR  27 ÷ 9.
My answer is 3! The mean of Lynn's data is 3!

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