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Hackernoon logoWhat We Need to Know About Standard Deviation & Distance Formula by@james-johnson

What We Need to Know About Standard Deviation & Distance Formula

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@james-johnsonJames Johnson

I am a researcher and a technical content writer. A math teacher since 2007. I love travelling, Love

Standard Deviation Elucidation: Standard deviation is particularly used to catch the values of dispersed data of a set. It shows the result in two states, whether the answer lies near or away from the reference or mean position.  It is important to realize that any Regular Distribution includes a Mean and Standard Deviation. The Regular Distribution is symmetrical about the Mean. The Standard Deviation determines the distribution's shape. 

The deviation is of two types:

  • Lower deviation 
  • Higher deviation 

Lower Deviation 

Represents the value approximately equal to mean observation.

Higher Deviation 

Refers to a great fluctuation rate of value from the observed mean value.

So, deviation liabilities fall in statistical calculations and mathematical curves as well. The value coming out from the deviational process can’t be negative.

Formulas of Standard Deviation

The standard deviation formula is generally used to figure out the common divergences. Including random variations, population instability monitorization, data set, and probability distribution. The formula is the square root of all mentioned components variance and should be written as:

𝛔 = √Σ i=1n(xi - x)2 / n-1


  • Xi = value of an ith position in the data set.
  • X bar = The mean value.
  • n-1 = number of data points in the data set.

Whereas, In most of the mathematical and statistical expressions or fluctuating reckoning, there two formulas split off deviation. 

  • Population Standard Deviation Formula (represented by Greek Letter 𝛔).
  • Sample Standard Deviation Formula (represented by Latin Letter s).

How to Calculate? 

Find the mean value (x bar): In a data set of numbers, adding all the data points and then dividing by the number of points present in the set. 

Find the Variance of each data point: Subtracting the data point from the calculated mean value. Each from these gathered values then squares root and divided by the total number of points minus 1. One can also use an online standard deviation calculator for free. 

Let’s Understand Through an Example

There are 5 dogs of various heights that are bracketed as 600mm, 170mm, 470mm, 430mm, and 300mm respectively. These heights are from their shoulders and the maximum rate is 600mm. So, first, we move to find the mean, variance, and at last the deviation in their heights. 

Mean = 600 + 170 + 470 + 430 + 300 / 5 = 394

So the mean or average height is 394 which is approximately 400 and derives the point differences of other values from this mean position. The variance we get are:


𝛔2 = (206)2 + (76)2 + (-224)2 + (36)2 + (-94)2 /5 = 21704

Standard Deviation:

It can be calculated as the final step by taking the square root of variance we concluded as above:

√𝛔 = √ 21704 = 147 (to the nearest value).

Distance Formula

In the geometrical analysis, distance formula gives us the distance between two points of an object.

In analytical geometry, the objects relatively consist of such infrastructure having XY-plane. This acquires dimensional properties in objects and dealing with their calculations become more accurate. Distancing between two points could be resolved by distance formula in mathematics.

Let’s suppose trigonometry has adjacent, hypotenuse, and opposite. Opposite and adjacent are considered as x and y planes while their end-points named as A and B. Distance formula calculator is an useful option but to find the distance between the component (x1, x2, y1, y2), the distance formula is as under:

d = √(Δx)2 + (Δy)2

d =  √( x2 - x1)2 + ( y2 - y1)2

If the third component is space then the distance formula for x, y and z could be:

d = √(Δx)2 + (Δy)2 + (Δz)2

d =  √( x2 - x1)2 + ( y2 - y1)2 + ( z2 - z1)2

Distance Formula in Physics

Likewise, there's an existing distance formula in physics, giving us an accurate distance for many conditions. It’s used to find out prominent or physical distances. The formula consists of:

d = v x t

Where v is the velocity of the object and t is the time in which distance has covered. 

Physics is interlocked with numerical margins and these basic formulas are commonly used when compensating with multi-directional numerical statements.

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@james-johnsonJames Johnson

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I am a researcher and a technical content writer. A math teacher since 2007. I love travelling, Love


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