0
$\begingroup$

I am wondering how I would calculate the standard deviation of a distribution when the values given are as below:

z = -1.08 
xi = 120 
x_bar = 122 
proportion = .14 

The missing element here is the standard deviation.

z-score:

z = (xi - x_bar) / std_dev

Using the available data - is there a way to rearrange it to solve for standard deviation?

Using algebra:

z = (xi - x_bar) / std_dev

z(std_dev) = (xi - x_bar)
-1.08 * (std_dev) = -2
-1.08 / -1.08 = -2 / -1.08  # divide both sides by z-score
std_dev = 1.85
$\endgroup$
1
  • 2
    $\begingroup$ Yes: use algebra. $\endgroup$
    – whuber
    Apr 25, 2020 at 16:07

1 Answer 1

0
$\begingroup$

Using algebra:

z = (xi - x_bar) / std_dev

z(std_dev) = (xi - x_bar)
-1.08 * (std_dev) = -2
-1.08 / -1.08 = -2 / -1.08  # divide both sides by z-score
std_dev = 1.85
$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.