The Mean Center tool is only available in ArcGIS Desktop applications, and there is no equivalent tool to find the mean center for simple point features in ArcGIS Online. However, there is a way to find the mean center of a group of point features in ArcGIS Online. The Find Centroid tool in ArcGIS Online is similar to the Mean Center tool in ArcGIS Desktop. When finding the mean center of a group of points, the Find Centroid tool only takes multipoint features as input.
To find the mean center using the Find Centroid tool in ArcGIS Online, follow the steps below:
Note: If the at the true centroid option is checked, a new point is created based on the x and y coordinates of all the points in the multipoint feature. If the contained by input features option is checked, the output centroid created is coincident to one of the points in the multipoint feature.