map_nhanes_pa_quantiles
                        Map physical activity values to NHANES
                        population quantiles
nhanes_measure_data     NHANES PA data
nhanes_measure_data_wear_criteria
                        NHANES PA data under alternative wear-time
                        inclusion criteria
nhanes_pa_age_category
                        Convert ages to NHANES physical activity CDF
                        age categories
nhanes_pa_measure_cdf   Select the NHANES CDF for a measure
nhanes_pa_measure_map   Supported physical activity measure names
nhanes_pa_quantile      Evaluate a single NHANES physical activity
                        quantile
nhanes_pa_wear_criteria
                        Available accelerometer wear-time inclusion
                        criteria
precompute_nhanes_pa_cdfs
                        Precompute and cache NHANES PA CDFs
