How to use Genetic Algorithm to solve discrete data for optimization?

Hello Everyone,

I have a question regarding Genetic Algorithm.

I have a data set for muffler optimisation in which I have calculated Transmission loss for various changes in muffler such as Inlet dia meter change and 5 other parameters for various frequiencies ranging from 60 Hz to 2000Hz. Each parameter is calculated for -15% to +15%.

change = [-15 , -10 , -5 , 0 , 5 , 10 , 15]; % Variable

input_length_RMSTL = [16.74 , 19.38 , 20.06 , 20.90 , 19.43 , 18.71 , 18.62];

output_length_RMSTL = [21.01 , 19.81 , 19.36 , 20.90 , 20.68 , 20.42 , 20.12];

muffler_length_RMSTL = [18.89 , 18.92 , 18.97 , 20.90 , 19.84 , 20.02 , 19.93];

input_dia_RMSTL = [18.77 , 19.47 , 18.98 , 20.90 , 19.56 , 19.68 , 19.99];

muffler_dia_RMSTL = [18.89 , 19.55 , 19.50 , 20.90 , 19.39 , 19.19 , 19.13];

output_dia_RMSTL = [18.99 , 19.24 , 19.49 , 20.90 , 19.46 , 19.52 , 19.77];

I have to optimise it using genetic algorithm. I have created function using curve fitting tool but this does seem to help as the curve is not properly fitting to all data points.

Can anybody help me with this problem?

Thanks in Advance.