EcoCalc1

Seven different components offer students a spreadsheet-like form into which data
can be typed or pasted. Values are recalculated after each data entry so students
can see the effect of single data items. The seven components include diversity
indices, community similarity indices, the Family Biotic Index of water quality, two-
sample comparisons (t-test), contingency table analysis of requencies, sample size
calculation, and life-table calculation.

Four measures of diversity are calculated (Simpson, Shannon, H'-max, Pielou
evenness), five measures of community similarity (Jaccard's, Sorenson's, Percent
Similarity, Morisita's, Horn's), three types of life table data can be entered (alive at
mid-chort, alive at start of cohort, dying during a cohort), and three biotic indices of
water quality (FBI, EPT Taxa, and EPT/Chironomidae).

Three components (Two-sample comparison, Contingency Table Analysis, and
Sample Size Calculation) focus on aspects of data analysis with particular attention
to appropriate procedures for field data. For example, the unpooled SEdifferences is
used to calculate t-scores as the assumption of equal variances is often
inappropriate in field studies.