Or, for a medical example, suppose smoking multiplies the risk of lung cancer by some number R: then the Wald test can be used to test whether R = 1 (i.e. there is no effect of smoking) or is greater (or less) than 1 (i.e. smoking alters risk).
There are more than 900 species of Tardigrade or Water Bear, pictured. They're found everywhere in the world, from the highest mountains to the deepest oceans. Boil the 1mm creatures, freeze them, dry them, expose them to radiation and they're so resilient they'll still be alive 200 years later.
A polar bear swam continuously for over nine days, covering 687km (426 miles), a new study has revealed. Scientists studying bears around the Beaufort sea, north of Alaska, claim this endurance feat could be a result of climate change. Polar bears are known to swim between land and sea ice floes to hunt seals.