1. A researcher is interested in whether students who attend private high schools have higher average SAT Scores than students in the general population. A random sample of 90 students at a private high school is tested and and a mean SAT score of 1030 is obtained. The average score for public high school student is 1000 (ó= 200).
a. Is this a one- or two tailed test?
It depends on what your alternate hypothesis is.
Ho: m1 = m2
Ha: m1 > m2 (one-tailed)
or
Ha: m1 ≠ m2 (two-tailed)
To determine whether this is a one-tailed or two-tailed test, we need to consider the research hypothesis. A one-tailed test is used when the research hypothesis predicts the direction of the difference, whereas a two-tailed test is used when the research hypothesis does not specify a direction.
In this case, the researcher is interested in whether students who attend private high schools have higher average SAT scores than students in the general population. The word "higher" suggests a specific direction, so it is a one-tailed test.
Therefore, the answer is: This is a one-tailed test.