The power trend line is very similar to the exponential curve, only it has a more symmetrical arc.

When adding a polynomial trendline in an Excel chart, you specify the degree by typing the corresponding number in the Order box on the Format Trendline pane, which is 2 by default:įor example, the quadratic polynomial trend is evident on the following graph that shows the relationship between the profit and the number of years the product has been on the market: rise in the beginning, peak in the middle and fall near the end. Typically, a quadratic polynomial trendline has one bend (hill or valley), a cubic polynomial has 1 or 2 bends, and a quartic polynomial has up to 3 bends. The degree of the polynomial trendline can also be determined by the number of bends on a graph. Generally, a polynomial is classified by the degree of the largest exponent. The polynomial curvilinear trendline works well for large data sets with oscillating values that have more than one rise and fall. It can include both positive and negative values.Īn example of a logarithmic trendline may be an inflation rate, which first is getting higher but after a while stabilizes. The logarithmic best-fit line is generally used to plot data that quickly increases or decreases and then levels off. Please note that an exponential trendline cannot be created for data that contains zeros or negative values.Ī good example of an exponential curve is the decay in the entire wild tiger population on the earth. This trendline type is often used in sciences, for example to visualize a human population growth or decline in wildlife populations. The exponential trendline is a curved line that illustrates a rise or fall in data values at an increasing rate, therefore the line is usually more curved at one side. And the R 2 value of 0.9855 indicates a pretty good fit of the estimated trendline values to the actual data. Typically, a linear trendline describes a continuous rise or fall over time.įor example, the following linear trendline shows a steady increase in sales over 6 months. The linear trend line is best to be used with linear data sets when the data points in a chart resemble a straight line. R-squared value measures the trendline reliability - the nearer R 2 is to 1, the better the trendline fits the data.īelow, you will find a brief description of each trendline type with chart examples.Trendline equation is a formula that finds a line that best fits the data points.

Additionally, Microsoft Excel allows displaying a trendline equation and R-squared value in a chart: When adding a trendline in Excel, you have 6 different options to choose from.

Write equation of trendline in excel