1.   Because the hygiene hypothesis is not proved, there are no recommendations yet to guide lifestyle changes.

2.   Also, William complained repeatedly that reporters were biased against him and he may have thought infiltrating them would prove his hypothesis.

3.   But scientists wondered how to prove the hypothesis.

4.   He formulated and proved a hypothesis that is analogous to it, but did not create the Riemann hypothesis itself.

5.   Scientists also proved his hypothesis that viruses could cause some human cancers.

6.   The researchers were surprised at how dramatically their hypothesis was proved, Andersen said.