It's an interactive tool that runs on pre-defined algorithms and gives you the final results live, quickly, and accurately. No need to do the manual calculations. Also, it's free to use. No subscription charges or calculation limits are there.
Mostly, we can use Standard Deviation Calculator to know whether someone's behavior is normal or extraordinary. In addition, it is used in many fields like finance, business statistics, weather changes, and many more.
In this article, I will provide you some very important information and techniques that will help you to understand the formulas and calculations.
Most importantly, we will discuss three things in this tutorial. Which are:
To solve the standard deviation issues firstly, we need to figure out mean and variance. That's why we will cover these two topics here. So, you can understand all the things clearly.
First of all, let me tell you the definition.
It is a number used to tell how measurements for a group are spread out from the mean value. In other words, it is a measure of how spread out the data is.
Its symbol is "σ". Also, we can call it "Sigma"(The greek alphabet).
The standard deviation calculator uses the following formulas to perform the calculation.
The "Population Standard Deviation":
The "Sample Standard Deviation":
Looks complicated right? No worries! I will help you to figure out all the things in very simple language.
Also, there is a small but very important difference between Population and Sample formula. That is "N" and "N-1" at denominator. Therefore, when we calculate sample variance, we need to divide by "N-1" (Instead of "N").
Here N is for population size and N-1 is for sample size. You can see it in the above formulas. Whereas other components are same in both equations.
Also, don't get confuse about "μ" and "x-bar(x̄)". Because these both are the same things. That is mean. x-bar is a sample mean and μ is population mean.
Don't be panic about names like population, sample, or mean. You will get all these complex things clear in the next section.
For easy understanding, I have divided the whole process into five simple steps.
First of all, let's take an example to understand above all steps one by one.
The following are the number of pens that five people have. So, find out the mean, the variance, and the standard deviation.
The values are: 22, 15, 35, 8, 10
In this example, we will calculate the population standard deviation.
First of all, let's have a look at the formula of standard deviation.
We can say that,
The standard deviation is equal to the square root of variance.
So, now you are aware of the formula and its components. Let's do the calculation using five simple steps.
First of all, let me tell you the meaning of mean.
The mean is an average of total numbers.
It is defined as "μ" (The greek letter mu). Also, it's very easy to calculate the mean.
Just add up all the given values and then divide it by a total number of values.
In our case, we have five numbers. So, we can calculate the mean like this.
So, the mean value = 18.
I am sure the first step is clear now. Let's jump to the next step.
In this step, we will subtract each data value with mean.
Here we have,
Xi data values = 22, 15, 35, 8, 10 and Mean(μ) = 18
So, now we will find (Xi - μ).
After subtraction, we get values = 4, -3, 17, -10, -8.
In this, we will square all the values that we get from step 2. So, it will be calculated like this:
Hence, we get the squared values = 16, 9, 289, 100, 64.
In this step, we will find the mean of squared values that we get from step 3.
But before we step forward, I want to tell you something.
Some of you will raise a question that:
What will we get from step 4?
Surprisingly, we will get Variance as a final output from step 4.
Now the question is What is Variance?
Let me show you the variance formula. So, you will get more ideas.
As you can see, we already have found the values of (Xi - μ)2. So, our next step is to calculate the variance using these squared values.
For that, we need to calculate the mean of squared values. In short, we need to sum up all the squared values and then divide it with a total number of values. That is 5.
Therefore, the calculation will be like this:
So, as a result, we get the variance = 95.6.
Now, let's go to the final step and find the standard deviation.
In this step, we just need to calculate the square root of variance.
Finally, we get the standard deviation value = 9.76 for population.
In this section, I will tell you the process to find the sample standard deviation.
First of all, let's have a look at the sample SD formula:
You can see, there is just a small change in this formula as compared to the population formula. That is "N-1" with replacing of "N".
So, we will skip step 1, 2, and 3 and directly calculate step 4 and 5. That is find out the sample variance using squared values and then square root the variance value.
We already have found the squared values from step 3.
Which are: 16 + 9 + 289 + 100 + 64
In population, we are dividing the above values with 5. Because the number of values is 5.
But in sample, we need to divide the squared total with (N-1) = (5-1) = 4.
After division, we will get the standard variance.
And then we need to calculate the square root of the variance to get the final Sample SD result.
You can see the step 4 and 5 calculation for sample standard deviation here:
I hope you will get all the things clear now. Also, you can easily do the manual calculation by following the five steps. But the manual calculation is only for our understanding. No need to do this all the time. Because it takes so much time to do it. So, use our calculator and save your time and effort.
It's very easy to use the calculator. Just follow these steps.
Isn't it simple? Yeah, it is. In short, you can use the standard deviation calculator and solve complex problems with few keystrokes.
The calculator is useless if the user interface is weak. That's why we provide the best user-friendly interface to our online users.
We made a simple design. So, any technical or non-technical person can use our tool easily.
Standard deviation calculator gives you a fast and 100% secure output. We also take care of data security of the people.
There are many advantages of this tool. Some of them are listed below.
Above all information was about standard deviation calculator. Hope it will work out and helpful for your study.