They are both equal to below zero
Answer:

Step-by-step explanation:
From the given information:
The sample size is 28
The population mean is 24.5 (ppb)
The sample mean is 225.3 (ppb)
Thus, the null and the alternative hypothesis can be computed as:
Null hypothesis:

Alternative hypothesis:

You line up the decimal points so that similar place values are lined up. it will be easier to add them.
8/5 or 1.6 you just need to find the rise over the run