How to find the right formula when given a few datapoints?

Question

Hiya,

Kind of a beginner question; I'm having trouble finding the right formula from a few given datapoints. Probably very easy to fix for some of you, but I'm really having trouble finding any good info on it.

I have 3 data points as input which comes down to the following;  
0.3 & 437.44 & x = 750  
4.16 & 437.44 & x = 1000  
1.265 & 437.44 & x = 425

Different example/different formula;  
1.8 & 437.44 & x = 1093  
2.6 & 656.16 & x = 2186

I need to both find out what the x value should be and also how the formula should be made up. I have no clue how I can make this fit aside from just trying stuff until i find something that works. There must be a better way to tackle problems like this, right?

TIA!

Answer 1

In the first 3, 3 of the numbers are the same. Start with those, using trial and error.

Answer 2

If this is a real world example, I would recommend looking at what the data represents.

If I have lots of values n1, n2 and r, I'm just fumbling about trying to find a relation but... if I know that n1 is the number of sunny days I operated my ice-cream truck in a month, n2 is the number of cloudy days I operated my ice-cream truck in a month and r is the amount of revenue I generated in that month then I could try to fit an equation of the form:

(n1)(r1) + (n2)(r2) = (r)

where r1 is the typical revenue I generate on a sunny day and r2 the typical revenue I generate on a cloudy day. and all that before looking at a single data point.