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Does null hypothesis determine whether p value for non directional or directional testing on hypothesis should be used?
Wiki User
∙ 11y ago
A null hypothesis is simply a postulate or, put another way, a possible statement of fact. It is a claim about something that might be accepted as true that is to be tested.
It does not determine in any way what decision method should be used to test whether it should be accepted. Therefore, it does not determine any aspect of the decision method that is used such as p value.
In general there are many rational ways of testing one hypothesis against another. Some of these ways will have better statistical properties than others; some might be cheaper or more convenient to perform. But none would be determined by the pair of hypotheses.
Wiki User
∙ 11y ago
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What is the directional and non-directional hypothesis testing?
In statistical hypothesis testing you have a null hypothesis against which you are testing an alternative. The hypothesis concerns one or more characteristics of the distribution. It is easier to illustrate the idea of directional and non-directional hypothesis. In studying the academic abilities of boys and girls the null hypothesis would be that boys and girls are equally able. One directional hypothesis would be that boys are more able. The non-directional alternative would be that there is a gender difference. You have no idea whether boys are more able or girls - only that they are not the same.
How do you determine directional or non-directional alternate hypotheses?
Whether you frame your alternative hypothesis, Ha, as one-sided (directional) or two-sided (non-directional) is really up to you, but should be decided before you look at the data. It will affect the calculation of your p-value and ultimately your conclusions from the test. In most cases there will be a sound, obvious reason for choosing one or the other.For example, if you were testing the effectiveness of a new anti-cholesterol drug you'd probably only be interested in testing whether the average of the experimental group was lower than the control group. So Ha is directional, or one sided. If on the other hand you were testing, for example, whether a Group A performed better on a test than Group B, your Ha would be that the average of Group A does not equal Group B. That is, you're not sure, before you run the test, whether Group A should perform better or worse than Group B. So your test is non-directional, or two-sided.
What is directional hypothesis?
A non-directional hypothesis only proposes a relationship. In contrast, a directional hypothesis also proposes a direction in the relationship. For example, when one variable increases, the other will decrease.
How do you decide whether to use a z test or a t test when testing a hypothesis about a population mean?
You use a z test when you are testing a hypothesis that is using proportions You use a t test when you are testing a hypothesis that is using means
Is the null hypothesis considered correct until proven otherwise?
No. The null hypothesis is not considered correct. It is an assumption, and hypothesis testing is a consistent meand of determining whether the data is sufficiently strong to say that it may be untrue. The data either supports the alternative hypothesis or it fails to reject it. See examples in links. Also note this quote from Wikipedia: "Statistical hypothesis testing is used to make a decision about whether the data contradicts the null hypothesis: this is called significance testing. A null hypothesis is never proven by such methods, as the absence of evidence against the null hypothesis does not establish it."
What is the directional and non-directional hypothesis testing?
In statistical hypothesis testing you have a null hypothesis against which you are testing an alternative. The hypothesis concerns one or more characteristics of the distribution. It is easier to illustrate the idea of directional and non-directional hypothesis. In studying the academic abilities of boys and girls the null hypothesis would be that boys and girls are equally able. One directional hypothesis would be that boys are more able. The non-directional alternative would be that there is a gender difference. You have no idea whether boys are more able or girls - only that they are not the same.
How do you determine directional or non-directional alternate hypotheses?
Whether you frame your alternative hypothesis, Ha, as one-sided (directional) or two-sided (non-directional) is really up to you, but should be decided before you look at the data. It will affect the calculation of your p-value and ultimately your conclusions from the test. In most cases there will be a sound, obvious reason for choosing one or the other.For example, if you were testing the effectiveness of a new anti-cholesterol drug you'd probably only be interested in testing whether the average of the experimental group was lower than the control group. So Ha is directional, or one sided. If on the other hand you were testing, for example, whether a Group A performed better on a test than Group B, your Ha would be that the average of Group A does not equal Group B. That is, you're not sure, before you run the test, whether Group A should perform better or worse than Group B. So your test is non-directional, or two-sided.
What is directional hypothesis?
A non-directional hypothesis only proposes a relationship. In contrast, a directional hypothesis also proposes a direction in the relationship. For example, when one variable increases, the other will decrease.
If group a has a higher mean than group b the research hypothesis is directional or non directional?
Whether your alternate hypothesis is directional (one-sided) or non-directional (two-sided) is largely up to you but must be determined before you conduct your experiment, not after. It's not defined by the outcome.
It Comes after a hypothesis and is used to determine whether the hypothesis is correct?
Test your hypothesis by Doing an Experiment
How do you decide whether to use a z test or a t test when testing a hypothesis about a population mean?
You use a z test when you are testing a hypothesis that is using proportions You use a t test when you are testing a hypothesis that is using means
What is the meaning of trial?
In terms of science, a trial is when a scientist begins testing whatever hypothesis he or she is investigating. The scientist will then study the data obtained, and determine whether or not the original hypothesis needs to be changed.
What is the significance of a hypothesis?
The significance test is the process used, by researchers, to determine whether the null hypothesis is rejected, in favor of the alternative research hypothesis, or not.
Is the null hypothesis considered correct until proven otherwise?
No. The null hypothesis is not considered correct. It is an assumption, and hypothesis testing is a consistent meand of determining whether the data is sufficiently strong to say that it may be untrue. The data either supports the alternative hypothesis or it fails to reject it. See examples in links. Also note this quote from Wikipedia: "Statistical hypothesis testing is used to make a decision about whether the data contradicts the null hypothesis: this is called significance testing. A null hypothesis is never proven by such methods, as the absence of evidence against the null hypothesis does not establish it."
What is the differnece between experimental hypothesis and directional hypothesis?
The experimental hypothesis, if stipulated like this, does not imply to be taking any specific direction in its prediction. Hence we will be in a situation were it will only refer to as either, a difference or a correlation only, the experiemntal hypothesis. However, if we decide to give direction to the experimental hypothesis, then we will have to add some information to the stipulation focusing on whether we predict that the difference involved will specifically cause an increase or decrease of the dependent variable(s), the directional hypothesis.
How do you come up with a hypothesis for a lab?
The lab would be used to test your hypothesis to whether or not you were correct. You would first want to form a hypothesis and then gather data to support or discredit your hypothesis. The hypothesis could be testing anything essentially.
How is a scientific hypothesis formed?
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