Mean, Median, Mode, Range, Outlier

I love this topic. It's very simple and very easy to work with. The only concept that is difficult is the "MEAN."

The most important thing you need to remember is to ALWAYS put the numbers in order from least to greatest.
...

I know I sound like a broken ____, but you MUST put the numbers in _____ (order)!

Let's get started:

MEAN: the MEAN is..very mean. It makes you do a lot of calculations! You need to add up ALL the numbers first, and then divide that sum by how many numbers you added.

MEDIAN: the MEDIAN is the MIDdle number. As you have the numbers in order, you need to work your way from the outside of both ends and find the middle number. Then, BAM! You are done! The only tricky part is when there are TWO middle numbers. When there are TWO middle numbers, you must..find the MEAN (add the two numbers, and then divide the sum by 2).

MODE: the MODE is the number that comes out the MOst. There can be more than one mode, or no mode at all! The number that comes out the MOst is the MOde.

RANGE: think: Home on the Range. Since you should have the numbers in order, all you do is subtract the biggest number of the group to the smallest number of the group.

OUTLIER: the OUTLIER is an OUTcast. It sticks out from the rest of the "crowd." When the outlier is lower than the rest of the numbers, the mean becomes lower. When the outlier is higher than the rest of the numbers, the mean becomes higher. Outliers do not affect the median nor the mode. Isn't that nice?

That's it! Not too shabby?

Again. I know I sound like a broken _____, but always remember...to put the numbers in ___.

Have fun reviewing (click on the links on the left side of the screen to practice)!

Circumference is the distance around a circle (perimeter).
A great way to remember this formula is by singing the "Twinkle Twinkle Little Star" song:

"Twinkle twinkle little star,
Circumference equals two pi r."

Formulas: πd or 2πr

remember: the radius is half the diameter, which is why EITHER of these formulas will work! Pretty groovy?
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Area is the space covered inside the shape, in this case, the circle.
We can use this rhyme to help us remember the formula:

"Fuzzy Wuzzy was a bear,
Area equals pi r squared."

Formula: πr^2

*Be careful. You must be able to correctly identify the diameter and radius and substitute the values into your formulas.

You can also click here to help you get extra help!

Simple Interest

Think: I PARTY!

I = Interest
P = Principal
R = Rate
T = Time (in years)

I = PrT

In order to find the simple interest, multiply the principal (the original amount), with the rate and time. Do NOT FORGET to move over the percent (rate) twice to calculate using a decimal.

Discount and Markup

To find the discount and markup, you do one simple operation: Multiply.

The only thing that is different is the next step: Finding the sale price vs. finding the selling price after the markup

Sale Price:
1. Multiply the original price by the percent of discount (don't forget to move the decimal over twice first!)
2. Subtract (think ¨Sale Subtract) the discount from the original price.


Markup:
1. Multiply the original price by the percent of markup (don't forget to move the decimal over twice first!!)
2. ADD (think MArkup - Multiply, Add) the markup price to the original price.

You should get a cheaper cost for the SALE price and a higher cost for the new SELLING price (after markUP).


Example:

1. A $30 sweater is 30% off. Find the sale price.

Step One: Multiply $30 by 0.30 = $9.00.
Step Two: Subtract (think SALE-SUBRACT) 30 - 9 = $21.

You save $9.00 and only pay $21 for the sweater after the discount.


Example:

2. A computer store buys a computer for $120 and markups the price by 20%. Find the new selling price.

Step One: Multiply $120 by 0.20 = 24 ($24.00)
Step Two: Add (think MArkUP - Multiply, Add) 120 + 24 = $144.

The computer store will charge $144 to the customers after the markUP.

BrainPop

Here is the link!

www.brainpop.com

Fractions, Decimals, Percents

I know fractions and decimals are not the most exciting concepts to learn, but they are important.

Trust me.

Use this as an example: 100% = 1.00 = 100/100

Percent means, "out of 100."



Some tips to remember;

Change Fraction to Decimal: "top in the box"

Example: 1/2 = 1 divided by 2 = 0.5

Change Fraction to a Percent: "top in the box", Move the decimal over to the RIGHT twice.

Example: 3/4 = 3 divided by 4 = 0.75 = 75%

Change Decimal to Fraction: Look at the place value and put it over either 10, 100, 1000, or so on

Example: 0.08 = 8/100 = 2/25

Change Decimal to Percent: Move the decimal over twice to the RIGHT

Example: 0.1 = 10 %

Change Percent to a Decimal: Move the decimal over tice to the LEFT

Example: 45.7% = 0.457

Change Percent to a Fraction: Put the number over 100 and reduce, if necessary, to its simplest form.

Example: 26% = 26/100 = 13/50