x1 = t1 is the elapsed time required for decaying/diminishing/reducing/shrinking population x2 = g1 to decrease in number by a factor of exactly/approximately 1/e^(x3) from that which is considered to be the initial population size, where e is the natural exponential base and x3 [li; default: 1] is a real number, according to standard/under condition/by model/in experiment x4; x1 is the one-(e^(x3))-th-life of population/sample x2; the (approximate) (x3)-th one-e-th-ing/e-fold decrease(/increase) of population x2 takes approximately x1 (time).
x1 = t1 is the elapsed time required for decaying/diminishing/reducing/shrinking population x2 = g1 to decrease in number by a factor of exactly/approximately half according to standard/under condition/by model/in experiment x3; x1 is the half-life of population/sample x2; the (approximate) halving of population x2 takes approximately x1 (dimensionful number: time).
x1 = t1 is the elapsed time required for decaying/diminishing/reducing/shrinking population x2 = g1 to decrease in number by a factor of exactly/approximately 1/(x3) from that which is considered to be the initial population size, where x3 [li; default: 1] is a positive real number, according to standard/under condition/by model/in experiment x4; x1 is the (x3^(-1))-th-life of population/sample x2; the (approximate) one-x3-th-ing/(x3)-fold decrease(/increase) of population x2 takes approximately x1 (time).
x1 (ordered list) is a sampling of entries of matrix/tensor x2 in which exactly one entry is sampled from each row and/or column (etc.) between entries x3 (list; default: the largest 'square'/'hypercubic' sampling possible in the entire tensor starting with the first entry, see notes) inclusively following selection procedure/rule/function/order x4 (default: diagonally, see notes), where the tensor/matrix is expressed in basis/under conditions x5
x1 is the standard variation of/in data set/distribution x2; x1 is the quantified (in)accuracy of the results x2 given by some observation or measurement (procedure), calculated from/by standard x3
x1 (collection, body, set, mass, tuple, n-some, etc.) is x2 (li; default: 1) indivisible/atomic/elementary/basic discrete entities (or particles) of type x3 in composition/content, by standard x4; the count of instances of x3 in x1 is x2 by standard x4.