Question

Can someone explain these standard deviation symbols?

Answer 1

Well, \(\overline x\) means "sample mean"

Answer 2

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.)

Answer 3

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

Answer 4

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 \(5\).

Answer 5

Trust Wio lol.

I just did quick google.