Worked example
A monitoring project reports twice as many beetle visits to logs on shaded plots as to logs on sunny plots during three damp mornings. A supported statement names the observed visits, plots and sampling window. The report does not distinguish shade from other site differences or tell whether the same beetles returned.
Contrast and common error
Consider a different claim: “Beetles gather only in shade.” A verified gathering in sunlight would challenge it. Finding an empty shaded plot would not. The first tests whether shade is necessary. The second tests whether shade alone is sufficient.
Transfer check
Two seed treatments have the same mean sprouting time. A report claims one treatment makes sprouting times more consistent. What evidence tests that claim? Check: record individual sprouting times under both treatments and compare their spread. Equal means can hide different variation.
Try it, then explain it.
Complete a short set without looking at the example. After each answer, explain which evidence or rule supports your decision and why the alternatives do not fit.
Sources & authorship
Original OpenExam explanations and examples. References support the concepts; they are not the source of copied questions. Independent educator review is pending.
OpenStax Biology 2e 1.1 The Science of Biology