I've collected some datasets for which I want to report a summary statistic.
I produced normal probability plots for the datasets, and the data does not conform to a Gaussian distribution - there are extremely long vertical tails for the lowest and highest values, and very few values correspond to the mean. Therefore, it appears the data follows an inverse bell curve (which I have come to learn is a speacial case of a bimodal distribution).
I need to select a single summary statistic to report the results of the datasets. Which summary statistic would be best to report results from an inverted bell curve?
EDIT: Here is an image of the distribution via the Normal Probability Plot: