## dtan5457 one year ago Can someone explain these standard deviation symbols?

1. dtan5457

2. geerky42

Well, $$\overline x$$ means "sample mean"

3. geerky42

And standard derivative is sum of all $$(x_i+\overline x)^2$$ divide by how many $$x_i$$ there are (there are 5 $$x_i$$'s in your table.)

4. anonymous

The $$\bar x$$ will be the same for every row.

5. anonymous

The mean $$\bar x$$ is just the average of the $$x_i$$ column. The variance $$\sigma^2$$ will be the average of the $$(x_i - \bar x)^2$$ column. The standard deviation $$\sigma$$ is just the square root of variance $$\sigma ^2$$. Since there are $$5$$ rows, average is just summing the column and dividing by $$5$$.

6. geerky42

Trust Wio lol. I just did quick google.