About $s_x$ and $s_y$

Question

What does $s_x$ and $s_y$ mean (e.g., in the picture below)? Is it a specific value from a column?

For instance if you have a table

fat    protein
-------------
14.0   16.4
10     12
13.5   10.2

Specific $S_x$ is 14 and $S_y$ is 16.4

You should add the `[self-study]` tag & read its [wiki](http://stats.stackexchange.com/tags/self-study/info). However, I don't think this Q needs to be closed in the interim. — gung - Reinstate Monica, Sep 26 '15 at 21:22
Which book is the page from? (I'd bet $s$ is defined quite clearly in it) — Glen_b, Sep 27 '15 at 00:10

Dawny33 · Answer 1 · 2015-09-27T06:19:57.317

2

$S_x$ is a general notion for "sample standard deviation".

It is considered when the data is only a sampling of the entire amount of data (population).

So when calculating it, it is divided by $(n - 1)$ at the end instead of $n$.

So, in your case, $S_x$ is the standard deviation of protein, and $S_y$ is the standard deviation of fat.

edited Sep 27 '15 at 06:19

answered Sep 26 '15 at 20:48

Dawny33

If you state that this value is standard deviation, then it will display as "S"? – What'sUP Sep 26 '15 at 21:07
**Standard deviation of a sample** And it is denoted by an S, followed by a subscript. In this case, as the two columns are taken as x and y, it would be Sx and Sy. Helpful reference for you: (http://stats.stackexchange.com/questions/269/what-is-the-difference-between-a-population-and-a-sample) – Dawny33 Sep 26 '15 at 21:11

1 Answers1