The following example shows an Order 2 polynomial trendline (one hill) to illustrate the relationship between speed and gasoline consumption. Order 3 generally has one or two hills or valleys. An Order 2 polynomial trendline generally has only one hill or valley. The order of the polynomial can be determined by the number of fluctuations in the data or by how many bends (hills and valleys) appear in the curve. It is useful, for example, for analyzing gains and losses over a large data set.

Note that the R-squared value is 0.9407, which is a relatively good fit of the line to the data.Ī polynomial trendline is a curved line that is used when data fluctuates. 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. A logarithmic trendline can use negative and/or positive values. Notice that the R-squared value is 0.9036, which is a good fit of the line to the data.Ī 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. In the following example, a linear trendline clearly shows that refrigerator sales have consistently risen over a 13-year period. A linear trendline usually shows that something is increasing or decreasing at a steady rate. Your data is linear if the pattern in its data points resembles a line. If you want, you can display this value on your chart.Ī linear trendline is a best-fit straight line that is used with simple linear data sets. When you fit a trendline to your data, Graph automatically calculates its R-squared value. Trendline reliability A trendline is most reliable when its R-squared value is at or near 1. The type of data you have determines the type of trendline you should use. When you want to add a trendline to a chart in Microsoft Graph, you can choose any of the six different trend/regression types.

Using excel trendline equation