Standard deviation is a measure of how spread out numbers are from the average. It is calculated using an equation for either a full population or a sample of a population. In an example, 5 pirates were surveyed about their gold coins, with amounts of 4, 2, 5, 8, and 6 coins. The mean was calculated as 5 coins. Then each amount was subtracted from the mean and squared. These squared differences were summed and divided by the sample size minus one, resulting in a standard deviation of 2.24 gold coins, representing the spread of coin amounts among the pirates.

1. Faculty Of Education
Elsa Kazi Campus
Presentation Topic: Standard Deviation
Name: Shamsa Laghari
Roll# 2k17/Bedsm/55
Assigned By: Dr. Amjad Ali Arain

2. CONTENT
• Definition
• Simple Example of Calculating Standard Deviation

3. Standard Deviation

4. Definition: Standard Deviation is the number used to tell how measurements
for a group are spread out the average (Mean),or accepted value. A low standard
deviation means that most of the numbers are very close to the average.A high
standard deviation means that the numbers are spread out.

5. Simple Example Of Calculating Standard
Deviation
• Let's say we wanted to calculate the standard deviation for the amounts of gold coins
pirates on a pirate ship have.
• There are 100 pirates on the ship. In statistical terms this means we have a population
of 100. If we know the amount of gold coins each of the 100 pirates have, we use
the standard deviation equation for an entire population:

6. What if we don't know the amount of gold coins each of the 100 pirates have? For
example, we only had enough time to ask 5 pirates how many gold coins they have. In
statistical terms this means we have a sample size of 5 and in this case we use
the standard deviation equation for a sample of a population:

7. The rest of this example will be done in the case where we have a sample size of 5
pirates, therefore we will be using the standard deviation equation for a sample of a
population.
Here are the amounts of gold coins the 5 pirates have:
4, 2, 5, 8, 6.
Now, let's calculate the standard deviation:

8. 2. Calculate for each value in the sample:
1. Calculate the Mean:
for each value in the sample:

9. 3. Calculate:
4. Calculate the Standard Deviation:

10. The standard deviation for the amounts of gold coins the pirates have is 2.24
gold coins.
Standard Deviation = 2.24 Gold Coins

11. Thank You