1. A computer-implemented method for mental state analysis comprising: obtaining mental state data from a plurality of people by capturing images of the plurality of people and analyzing the images to determine the mental state data, wherein, for at least one person of the plurality of people, the capturing is performed while the at least one person views a media presentation; analyzing the mental state data to produce mental state information for the plurality of people; generating a metric based on the mental state information; generating a statistical analysis for the metric by resampling data from the mental state information by randomly sampling a specific number of times from the mental state information; modifying the media presentation based on the metric; evaluating a norm, on a computing device, based on the metric, wherein the evaluating the norm is based on resampling data from the mental state information from the plurality of people multiple times where the resampling includes random selection of data from the mental state information and where individuals from the plurality of people are selectively omitted from the resampling and where a synthetic trace is generated based on the resampling and the synthetic trace indicates emotional reactions for grouped subsets of people within the plurality of people and the synthetic trace is used in the evaluating of the norm; and rendering an output of the norm on a display.