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.
Meet the toughest animal on the planet: The water bear that can survive being frozen or boiled, float around in space and live for 200 years (shame it isn't much to look at) Published: 20:31 EDT, 17 February 2013 | Updated: 06:20 EDT, 18 February 2013.