When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
How does that happen A study has two evidence factors if it provides two statistically independent tests of one causal hypothesis, susceptible to different biases. Two evidence factors can jointly provide quantifiably stronger evidence than either factor can provide on its own.
When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.