At Baseball Daily Digest, I find out just how amazing the first month’s grand slam pandemonium really is.
From 2001-08, an average of 130 home runs with a standard deviation of 5 were hit in that time span, in an average of nearly 4,900 plate appearances. This season’s 31 grand slams in just over 850 plate appearances puts us on pace for 177 salamis, a total not seen since the beginning of the decade when 176 were hit in 2000.
With an average of 130 slams and a standard deviation of 5, that puts this season’s pace more than 9 standard deviations above the mean — clearly an outlier. In a normal distribution, 99% of our data points can be found within three standard deviations above or below the mean — that’s how outrageous the first month has been for us so far.