Choosing which trendline to use

Cubic Order 3 has two curves. If your data values don't resemble a straight line or a fluctuating curve but increase or decrease rapidly then consider either exponential , logarithmic , or power. If your data increases at an increasing rate or decreases at a decreasing rate, then exponential might be a good fit. The exponential curve cannot take zeros or negative values. If your data increases rapidly but then flattens to a plateau, logarithmic might be a good fit. If your data plot looks exponential and logarithmic, you might also want to consider changing one of your axes to a log scale.

You can learn more about log scales in our 3-part blog post about log scale. You can either turn one axis into a log scale or both axes into log scales and selecting the following options will draw a straight-line correlation between the two variables.

These are just some general hints and there are many other ways to calculate and determine the best-fit trend line for your data. If you want to know how the trend lines are calculated in Datawrapper, they are based on the Javascript module r egression-js so take a look at their GitHub page for details. If you have any questions, reach out to us at support datawrapper.

Without going into stats too much, Tableau is computing how well your trend line fits the model based on an F statistic with a hypothesis that an intercept only model is accurate. If P is low we reject this and fail to reject or accept, but we can never truly accept a hypothesis the alternate option that this trend line accurately describes the data.

A low p value may be a bad thing as the line may not be the best model to follow. To put it another way, there is a 1-p chance that the coefficient of the trend line is not 0.

The five different types of trend lines are: 1. Linear 2. Polynomial 3. Exponential 4. Logarithmic 5. This will open another window where trendline types are available. You can choose the one which suits the chart you created.

Another option is to click your chart and look at your Excel menu bar. Head on to the added tab, Chart Tools, and in the Design tab, click Add Chart Element where another drop down list will appear.

At the bottom part of this, you will see Trendline, click this for a list of options that will best fit your data. Whatever your reports, it is easier to spot the direction of values when you use graphical tools to show data. This ensures that reports are easily understood, along with the trend at which your values are headed as a result of the lines appearing in the chart. The ability to fully grasp the value and use of trendlines and other Excel functions will allow you to use your computer programs to unlimited use.

Want to know more? Get in touch! Skip to content. The type of data you have determines the type of trendline you should use. Trendline reliability A trendline is most reliable when its R-squared value is at or near 1. When you fit a trendline to your data, Graph automatically calculates its R-squared value. If you want, you can display this value on your chart. A linear trendline is a best-fit straight line that is used with simple linear data sets.

Your data is linear if the pattern in its data points resembles a line. A linear trendline usually shows that something is increasing or decreasing at a steady rate. In the following example, a linear trendline clearly shows that refrigerator sales have consistently risen over a year period.

Notice that the R-squared value is 0. A logarithmic trendline is a best-fit curved line that is most useful when the rate of change in the data increases or decreases quickly and then levels out.

The following example uses a logarithmic trendline to illustrate predicted population growth of animals in a fixed-space area, where population leveled out as space for the animals decreased.

Note that the R-squared value is 0. A polynomial trendline is a curved line that is used when data fluctuates.