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##### Asked by: Yaeko Inderdohnen

science physics# How do you find the proportion of one standard deviation?

**a**normaldistribution's values are within

**one standarddeviation**ofthe mean. 95% are within two

**standarddeviations**and 99.7%are within three

**standarddeviations**. That means that the

**proportion**of valueswithin

**one standard deviation**is68/100 = 17/25.

Similarly, it is asked, how do you find the percentage of one standard deviation?

The Empirical Rule or 68-95-99.7% Rule can give us agoodstarting point. This rule tells us that around 68% of the datawillfall **within** one **standard deviation** of the mean;around95% will fall **within** two **standard deviations**of themean; and 99.7% will fall **within** three**standarddeviations** of the mean.

**data**set with a symmetric distribution,approximately 68.3

**percent**of the values willfall

**within**one

**standard deviation**from the

**mean**,approximately 95.4

**percent**will fall

**within 2standarddeviations**from the

**mean**, and approximately99.7

**percent**will fall

**within**3

**standarddeviations**from the

**mean**.

Moreover, how do you find the standard deviation of a sample size?

**First, let's review the steps for calculating thesamplestandard deviation:**

- Calculate the mean (simple average of the numbers).
- For each number: subtract the mean.
- Add up all of the squared results.
- Divide this sum by one less than the number of data points (N-1).

The **standard deviation** is given bythe**formula**: s means '**standard deviation**'. Now,subtractthe mean individually from each of the numbers given andsquare theresult. This is equivalent to the (x - )²step.