posted by lashawn .
Then, for the following two examples, determine the null and alternative as well as state which one represents the claim. State what type of test will be completed: left-tailed, right-tailed, or two-tailed.
The average score of the first exam for the class is an 81%.Claim 2: The average price for a gallon of gas is more than $3.00.
It depends on what question you are asking.
Ho: mean = 81%
Ha: mean ≠ 81%
Ho: mean = $3.00
Ha: mean > $3.00
I'm not sure what you mean by right-tailed or left-tailed. I don't use those specific terms.
Upon further thought, right-tailed may be the equivalent to positively skewed (deviant scores at higher values). If so, the second Ha would be right-tailed.
The mean is influenced by deviant scores, like a fulcrum (balance point). Thus Ha for "more than $3.00" would be looking for a higher mean and "right-tailed."