For all three alternatives, the null hypothesis is o: = o.
State Null and Alternative Hypotheses
A good hypothesis statement should:
Krista,
I’m not sure what your question is. You list quite a few (identify null, alternate, test status, pvalue or critical). Are you having trouble identifying the null and alternate hypotheses? Or is it that you don’t know what test to run?
BTW: both the critical value and pvalue will give you the same results. I’d just choose one and go from there.
Stephanie
Photo provided by Flickr
Alternative hypothesis – SCL will have a significance effect on how primary school students learn English skills compared to when they’re taught using a teachercentered approach
State Null and Alternative Hypotheses
Photo provided by Flickr
If our statistical analysis shows that the significance level is below the cutoff value we have set (e.g., either 0.05 or 0.01), we reject the null hypothesis and accept the alternative hypothesis. Alternatively, if the significance level is above the cutoff value, we fail to reject the null hypothesis and cannot accept the alternative hypothesis. You should note that you cannot accept the null hypothesis, but only find evidence against it.
If you are going to propose a hypothesis, it’s customary to write a statement. Your statement will look like this:
“If I…(do this to an )….then (this will happen to the ).”
For example:
State Null and Alternative Hypotheses
Photo provided by Flickr
Depending on how you want to "summarize" the exam performances will determine how you might want to write a more specific null and alternative hypothesis. For example, you could compare the mean exam performance of each group (i.e., the "seminar" group and the "lecturesonly" group). This is what we will demonstrate here, but other options include comparing the distributions, medians, amongst other things. As such, we can state:
We usually set the hypothesis that one wants to conclude as the alternative hypothesis, also called the research hypothesis. The above example is about population proportion and thus we set up the hypotheses in terms of .
Photo provided by Flickr
Step 1: State Null and Alternative Hypotheses.

State Null and Alternative Hypotheses
The null hypothesis is usually stated as the absence of a difference or an effect.

I’m stuck on how to value the null or alternative hypotheses
Many authors talk about rejecting the null hypothesis in favor of the alternative.

rejecting the null hypothesis when the alternative is true.
If, for example, the null hypothesis says two population means are equal, the alternative says the means are unequal.
not rejecting the null hypothesis when the alternative is true.
By tradition, we try to disprove (reject) the null hypothesis. We can never prove a null hypothesis, because it is impossible to prove something does not exist. We can disprove something does not exist by finding an example of it. Therefore, in research we try to disprove the null hypothesis. When we do find that a relationship (or difference) exists then we reject the null and accept the alternative. If we do not find that a relationship (or difference) exists, we fail to reject the null hypothesis (and go with it). We never say we accept the null hypothesis because it is never possible to prove something does not exist. That is why we say that we failed to reject the null hypothesis, rather than we accepted it.
Learn About Null Hypothesis and Alternative Hypothesis
The null hypothesis is essentially the "devil's advocate" position. That is, it assumes that whatever you are trying to prove did not happen (hint: it usually states that something equals zero). For example, the two different teaching methods did not result in different exam performances (i.e., zero difference). Another example might be that there is no relationship between anxiety and athletic performance (i.e., the slope is zero). The alternative hypothesis states the opposite and is usually the hypothesis you are trying to prove (e.g., the two different teaching methods did result in different exam performances). Initially, you can state these hypotheses in more general terms (e.g., using terms like "effect", "relationship", etc.), as shown below for the teaching methods example:
The alternative hypothesis is typically the research hypothesis of ..
When debating the State Appropriation for Penn State, the following question is asked: "Is the majority of students at Penn State from Pennsylvania?" To answer this question, we can set it up as a hypothesis testing problem and use data collected to answer it.
State Null and Alternative Hypotheses.
Now that you have identified the null and alternative hypotheses, you need to find evidence and develop a strategy for declaring your "support" for either the null or alternative hypothesis. We can do this using some statistical theory and some arbitrary cutoff points. Both these issues are dealt with next.