MATLAB: How to modify data from a loaded file and then plot it

Question

I would like to convert the Y data into a logarithms and then multiply them by 20. I want the resultant data to be plotted with the X data unchanged. Something like this:

Y(new) = 20 * Log10(Y)
X(new) = X

Answer 1

Y_new = 20 * log10(Y);
plot(X, Y_new);