An observational study determined that there is a strong correlation between getting less than 8 hours of sleep a day and lower test scores. Can it be determined that the low test scores are caused by sleep deprivation? Explain.

15 points ! ~ see if you know the answer to both you!

David estimated he had about 20 fish in his pond. a year later, there were about 1.5 times as many fish. the year after that, the number of fish increased by a factor of 1.5 again. the number of fish is modeled by f(x)=20(1.5)^x. create a question you could ask that could be answered only by graphing or using a logarithm.

For the sequence [tex]a_{n} = 2n/(n+1)[/tex], what is the value of [tex]a_{10}[/tex]