Szekessy Vilmos (szerk.): A Magyar Természettudományi Múzeum évkönyve 53. (Budapest 1961)

Pócs, T.: The calculation of the quantitative grade of efficacy of collecting and extracting methods of materials used in zoocoenology

two subsequent methods do not refer to the same species, as, for instance, the use of light-traps and baits). Let us start from the total number of individuals existing in one of the habitat or sample portions. Let this value be designated S

x

. Selecting by the first method, of an x grade of efficacy, we receive an number of individuals. There remained in the mass, that is, biotope, an number of individuals. Of this residue, we receive, by the use another method of an y grade of efficacy, an (S

l — Six) y number of individuals. These two values are known factors, directly receivable from the experiment. Let the quotient of the numbers of individuals received from the second and first extractions be designated B : On the other sample, that is, sample area, the two extractions will be made in a reverse order. Let the total number of the individuals of the second sample area, that is, sample be designated S

2

. By first using the method of an y grade of efficacy, we receive an S

2

y number of individuals. There remained in the sample an S

2 — S

2

y number of individuals. Extracting the residue by a method of an x grade of efficacy, we receive an (S — S

2

y) x number of individuals. The quotient of the numbers of individuals received from the second and first extractions may be designated as C : By the uniting of the two equations, we receive the x and y efficacy-grade constants of the two methods applied : X unknown expressed from the right equation Substituted into the left equation : Multiplied by y, that is, B ' Multiplied by ( Reduced to 0 Divided by y, and changing the sign