Why can you not prove a hypothesis

To conclude, you cannot prove a hypothesis because you can never generalise the results to the whole population and foresee the results will always be the same in the future. You can however, reject the null hypothesis consistently, through statistical hypothesis testing so that the theory becomes highly likely to be true, but not proven.

Explanation:

"1. it should be, it has been for about 20 years, and it's really not much different in the end than breeding animals to have particular traits. there are always concerns about genetically engineered animals/plants affecting the environment in unexpected negative ways, but i can't think of an example where the fears didn't turn out to be baseless.  

first, as you point out, it would be a great advance in pharmacology, to be able to tailor drugs and their doses to me. the pros involve better medical treatment. the cons involve privacy issues like insurance companies denying coverage to people with genetic risk factors. looking at dna markers wouldn't affect the frequency of genetic diseases, but it would allow detection of them earlier. and ok, actually i suppose that if people used this information to avoid having children with genetic diseases, some might decrease in frequency."

just finished the test, the answer is d, greg is the least cost-effective because he charges the most for the project