The luteal phase of the menstrual cycle is about the same length in most individuals (mean 14.13 days, SD 1.41 days) whereas the follicular phase tends to show much more variability (log-normally distributed with 95% of individuals having follicular phases between 10.3 and 16.3 days).
The minimum size joist to be used in deck construction is not a stand-alone consideration, and is related to the number of footings and beams that will be installed. In general terms, joists spaced 16 inches on center can span 1.5 times in feet their depth in inches. A 2x8 up to 12 feet; 2x10 to 15 feet and 2x12 to 18 feet. The larger the deck, the larger the joists. In typical deck construction, with a ledger on one side of the joist and beam on the other, the size of the joists is driven by the size of the deck based on the general maximum spans mentioned above.
If the span is long for the material used, 12 on center is possible, or even 8. If the span is short relative to the material used for joists, 19.2 (19 3/8) spacing or even 24 spacing may be acceptable. Proper spacing depends upon what kind and size of floor joists you have and the span of the floor joists.