Introduction -- Density : mean and variance -- Normal and sampling distributions for fieldwork -- Confidence limits and intervals for density -- How many field samples? -- Spatial distribution : the ...

primary - information that you collect yourself, eg tallies, measurements and photographs secondary - information that someone else has previously collected and made available, eg on the internet The ...

The Nature Index 2025 Research Leaders — previously known as Annual Tables — reveal the leading institutions and countries/territories in the natural and health sciences, according to their output in ...