Summary statistics, whether mean, standard deviation or any other single number, are useful, but sometimes they can mislead - vastly different data sets can have similar or even identical summary statistics. In the video below Robert Kosara discusses this phenomenon in more detail.
Thus here we give you an opposite advice to the one we gave previously. You should plot the data to see whether summary statistic you have obtained make sense.
Well, you should actually always do both things - visualize the data and do some tests or summarization. If intuition from the visuals and the numbers differs, then you should look for things that may have gone wrong.