Getting Excel To Read Smoothed Lines in a graph

[glint]

Hi there.
New to the forum so not sure whether this has been asked before. Sorry if it has. Hope it makes sense.

I have created a graph using six sets of actual sample data. its a simple graph of cost against size (x). As it happens, the larger the item is, the more it costs. (bizarre i know ).
It isnt linear though, and i have used a scatter graph with smoothed lines and the graph is fine.

What i would like to know is this, Is there a way of using the smoothed line i have created to give me costs for other sizes. Ie interpolate between my sample sizes, and give me a cost for any given size?

Or, am i overcomplicating things? Should i be doing it a different way?

hope you can help

 

[PA HS Teacher]

Have you added some sort of trendline?

- sounds like its not linear
- a polynomial perhaps.

In anycase, do you have the equation for this line. (did you check the button to include the equation on the graph when you put in the fit line)

This equation can be used to interpolate or extrapolate data.

 

[glint]

no, its not a 'trendline' as such, its a scattergraph and i chose the option of smoothed lines.

If i could replicate it with the formula that would help imensely. I cant find the tick box though. Where is it?

 

[PA HS Teacher]

Right Click on one of the data points, and choose Add Trendline. Based on your description I would choose a polynomial fit line. There should be a checkbox for placing the equation on the graph in addition to the trendline.

 

[glint]

Thanks for that, i changed my line to a polynomial trendline as suggested, identified the formula and solved the problem.

thanks again