All language subtitles for 04 - Add trendlines to charts

- [Curtis] Whenever you collect data

in Microsoft Excel or another program,

you should always examine it for trends.

In this movie,

I will show you how to examine your data visually

by adding a trend line to a chart.

My sample file is 02_04_trendline.

And you can find it in the chapter two folder

of the Exercise files collection.

In this workbook, I have a worksheet with a table of data.

And I have the distance

that a customer traveled to get to your store

and then the amount that they spent once they were there.

And if I scroll down,

you can see that the customer who traveled

the farthest came from 152 miles away and spent $195.

I've already created an XY scatter chart

to show the relationship between distance and amount spent.

And you can see that there is a fairly clear relationship.

If you want to find a line that best fits the data,

you can add a trendline to your chart.

To do that, I will click the body of the chart.

And then on the Chart Design contextual tab on the ribbon,

I will go to the far left and click Add Chart Element,

and then point to trendline, and then click Linear.

That's because I know that the data

in this particular dataset is linear.

So I'll go ahead and click that.

And I can see the trendline.

And in this case,

it turns out that the trendline intersects

almost exactly with the last data point in the set.

That doesn't usually happen.

So if it doesn't for your data, don't worry about it.

So what this trendline tells you is that an individual

who travels approximately 120 miles is likely to spend

a little bit over $150, probably very close to 160.

Where if they traveled 60 miles,

they will most likely spend about 85 to $90.

And again,

this is a line that is designed to show you the trend,

even though some values are going to be far from the line.

And you can see for this point

where someone traveled 100 miles and spent $200,

that's far from the average.

So they spent more than expected,

but another customer who traveled

about the same distance spent less than expected.

If you want to change the format

or appearance of your trendline,

you can go to the Chart Elements control,

point to Trendline,

and then click the arrow that appears to the side,

and then click More Options.

That opens the Format Trendline task pain.

And you can change elements

of it such as, for example, forecasting.

In this case because we don't have time series data,

it doesn't actually make sense to use a forecast

for values outside of your data range.

We have collected data on individuals who traveled

up to 150 miles to get to your store.

And the question is, if this trend holds,

if someone travels say 300 miles,

would they actually spend $400 typically?

That doesn't seem likely.

And that's a sort of judgment

you have to make about your business.

So even so,

you should limit your predictions to the dataset

and data range that you have.

If someone travels 160 miles,

even though it's more than 152,

you can probably make reasonable assumptions

about how much they're going to spend.