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.
Periodical cicadas, sometimes called 17-year locusts, emerge from the ground by the thousands every 13 or 17 years. The cicada nymphs cover trees, shrubs, and other plants, and then molt into adulthood.Adult males congregate in loud choruses, and fly together in search of females.nswer: Periodical cicada nymphs feed underground on tree roots, but will not cause significant damage to your landscape trees. In fact, the cicada nymphs help aerate the soil, and bring nutrients and nitrogen to the surface, benefiting plants.