## Sample Standard Deviation

Calculate the standard deviation for the sample values: 4, 2, 9

##
__
__**Hint**

**Hint**

Sample standard deviation:

$$$s =\sqrt{\frac{1}{n-1}\sum_{i=1}^{n} (X_{1}-\mu )^{2}}$$$

where
$$n$$
is the number of items or observations,
$$X$$
is the value from the set, and
$$\mu$$
is the mean.

##
__
__**Hint 2**

**Hint 2**

We can set up the following table:

First, let's find the mean of all the values:
$$(4+2+9)/3=5$$

We can set up the following table:

Because these are sample values, the standard deviation formula is:

$$$s =\sqrt{\frac{1}{n-1}\sum_{i=1}^{n} (X_{1}-\mu )^{2}}$$$

where
$$n$$
is the number of items or observations,
$$X$$
is the value from the set, and
$$\mu$$
is the mean. Do not confuse this with a population standard deviation. Plugging the values from the table:

$$$\sigma =\sqrt{\frac{(1+9+16)}{3-1}}=\sqrt{\frac{26}{2}}=3.6$$$

3.6