Now we need to add the mean and standard deviation lines to our graph.

In this case, this is done by adding what are called reference lines in Tableau,

and the way that we add a reference lines is by right-clicking

on the y-axis and selecting add reference line.

To start out with, we're going to add the mean reference line to our graph,

and this is extremely easy to do in Tableau because that

is the default reference line that they'd like you to add.

So, it's a line, it's computed over the temperatures,

and we want the average.

We don't need to change the way that the line looks because we just want the line.

So, let's click okay and see what that gives us.

Here, we can see that Tableau has added an average line to our graph,

and the average falls at 11.19 which is exactly what we'd expect.

Now let's add the standard deviation lines to the graph.

We're going to add another reference line.

But in this case, the standard deviation doesn't come up

in the possible computations for our lines.

What we have to do is we have to add a distribution,

and that distribution occurs over the standard deviation.

Negative one and one is correct because we want them to go from

one standard deviation above to one standard deviation below.

However, Tableau by default has a sort of distribution band

here between the positive one and negative one standard deviation,

but we don't really want that.

For our control chart, what we're looking for is we're looking for individual lines.

So, we can change the formatting to a solid line and make

it orange just like we made the line in Jupyter Notebook,

and remove the fill.

This gives us our one standard deviation line.

To add our two standard deviation lines,

we add another reference line at another distribution.

But in this case, we're going to go to

standard deviation and our factor will be negative two and two.