The sum of the absolute frequencies is equal to the total number of data, represented bas $$N$$. 1  Relative frequency: the result of dividing the absolute frequency of a certain value by the total number of data.  The sum of the relative frequencies is equal to $$1$$. We can prove this easily by factorizing $$N$$.
Periodical cicadas emerge from underground every 13 or 17 years, depending upon which brood the cicadas belong to. The year a particular brood emerges often differs from other broods and is also dependent on geography. The periodical cicada, although unrelated, is often mistakenly called a locust.
Why do 17-year cicadas come out more often than every 17 years? A cicada gets up close and personal with this teenage boy. Fortunately, it's harmless. During a May 7, 2013, concert for 47,000 fans at an open-air stadium in Brazil, McCartney's stage was swarmed by scores of insects.