function sem=standard_err(input_data)
%description: returns the standard error of the mean, saving a few words in the calling program
%called by: analyze_and_plot_mean_responses, latency_summarizer, change_point_data_plotter(deprecated), plot_mean_raw_traces(deprecated)
%calls:
%notes:
%code confirmed date: oct 8, 2009

sem=std(input_data)/sqrt(length(input_data));