Help calculating percent error at different times

I have two arrays that are 1 x 81. The arrays are named theoretical and analytic. The last column value for analytic is 5.50. The last column value for theoretical is 5.45. Currently, I have a step function that calculates the years from 0 to 20000 with 80 steps. How would I calculate the percent error between the analytical and theoretical values for different points in time, ie: years = 50, 250, 500, 750, 1000?

[darova]

What about interp1?

[Ganesh Regoti]

Hi,

Have you tried interp1? And to generate a function you can use polyfit given x and y values