1. Statistics
Tutorial

2. Statistics
Probability and Statistics can be very complicated, but we are going to focus on the more basic problems such as mean and median. We will also show how to solve a very simple probability problem.
Let’s get started with a couple of definitions:

3. Statistics
The mean of a set of numbers is the average. You can find the mean or average of a set of numbers by adding them all together and dividing the sum by the amount of numbers you added together.
The median of a set of numbers is the middle number. If you list all the numbers in order, the median is the middle of the list. That’s easy if it is an odd amount of numbers. But what if you have an even amount of numbers? In that case, average the two numbers in the middle.

4. Statistics Mean Examples
Let’s find the mean of the following sets of numbers.
24, 37, 39, 12, 88
First we add all the numbers together.
= 200
Now since there are 5 numbers, we divide the answer by 5
200 / 5 = 40
So the mean of 24, 37, 39, 12, is 40

5. Statistics
Let’s try another one. What is the mean of the following numbers?
17, 83, 52, 25, 23, 70
= 270
270 / 6 = 45

6. Statistics Median Examples
Now lets find the median using the same numbers as above.
24, 37, 39, 12, 88
First we need to put them in numerical order.
12, 24, 37, 39, 88
Now it’s easy to see the middle number, which is 37

7. Statistics
That was easy since we had an odd amount of numbers. But what if we have an even amount of numbers? Remember what to do?
Let’s find the median of these numbers.
17, 83, 52, 26, 23, 70

8. Statistics Once again, we need to put them in numerical order.
17, 23, 26, 52, 70, 83
However, since we have no number directly in the middle, we take the number on either side of the middle and average them together…or we find the mean of those two numbers.
= 78
78 / 2 = 39
So the median of 17, 23, 26, 52, 70, 83 is 39

9. Statistics Probability Examples
We will use the same example here that you saw in the Practice Test and explain it for you.
Problem: If you roll a die once, what are the chances that you would get a 5?
First we know that dice have 6 sides with a different number on each side.

10. Statistics
Since there are 6 sides, and you are only rolling it once, you have a 1 in 6 chance that you will get a 5. We can represent this with the fraction 1/6
But what if you had an alien die that has eight sides, and has the following numbers?

11. Statistics
What is the probability that if I will get a 2 if I roll this die once?
How many twos are there? 3
How many sides are there? 8
So I have 3 chances in 8…or 3/8
Using the same alien die, what is the probability that I would get a 9 if I roll it once?
If you came up with 1/8 you are right!

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Statistics
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