RESPOND IN 300 WORDS:
A situation in which I would test a directional hypothesis would be a drug company’s new antidepressant. The directional hypothesis I would test is that the drug helps those dealing with symptoms of depression in a positive way, either by reducing or eliminating depressive moods, thoughts, and/or behaviors. The independent variables would be whether or not a participant in the study received the drug or the placebo. The dependent variables would be whether or not the drug affects the participants moods, thoughts, and/or behaviors. This hypothesis is directional because it states that the drug positively affects the participants moods, thoughts, and/or behaviors; therefore, I am operating under the assumption that the drug either does these things or simply does not do them.
Using the same situation, I could create a nondirectional hypothesis: the new antidepressant will have an effect on the participants moods, thoughts, and/or behaviors. The independent and dependent variables remain the same; however, my hypothesis is now a nondirectional one. It is nondirectional because it states the drug will have some effect, but does not say what that effect will be, thus I am not stating which direction I expect the results to go.
The more appropriate test, in my opinion, is a one-tailed directional test. This is because I specifically want to know whether or not this drug is going to positively effect the participants.
It is important, in regards to a two-tailed test, to alter the alpha level to create a rejection region of 5%, instead of having a total of 10%. As stated in our lectures, in a two-tailed test, we would “reject the mean for a total of 10% of the scores and not just 5%.” In addition, the tails on a two-tailed test are commonly smaller than a one-tailed test, thus in order to reject the null, the “test statistic needs to be a more extreme score.”
IN 300 WORDS, RESPOND:
A new antidepressant from a pharmaceutical company would be a case in which I would test a directional hypothesis. The directional hypothesis I’d investigate is that the medicine benefits those who are suffering from depression symptoms by reducing or eliminating depressive moods, thoughts, and/or actions. Whether or not a participant in the trial received the medicine or the placebo would be the independent variable. The drug’s effect on the participants’ moods, thoughts, and/or behaviors would be the dependent variables. This hypothesis is directed since it states that the drug has a favorable effect on the participants’ moods, thoughts, and/or behaviors; as a result, I am assuming that the drug either does or does not do these things.
Using the identical scenario, I could come up with a nondirectional hypothesis: the new antidepressant will affect the participants’ moods, thoughts, and/or behaviors. My hypothesis is now nondirectional, but the independent and dependent variables remain the same. It’s nondirectional because it says the drug will have an effect but doesn’t specify what that effect will be, therefore I’m not predicting which way the findings will go.
A one-tailed directional test, in my opinion, is the more appropriate test. This is because I’m curious as to whether or not this medicine will have a favorable impact on the participants.
In a two-tailed test, it’s critical to change the alpha level to generate a rejection zone of 5% instead of a total of 10%. In a two-tailed test, we would “reject the mean for a total of 10% of the scores, not simply 5%,” as indicated in our lectures. Furthermore, because the tails of a two-tailed test are typically narrower than those of a one-tailed test, the “test statistic needs to be a more severe score” to reject the null hypothesis.
