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A statistician may have some idea about some statistics in a data set, and there is a need to test whether or not that hypothesis is likely to be true. Data are collected and a test statistic is calculated. The value of this test statistic is used to determine the probability that the hypothesis is true.
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What is the basic requirement of a scientific hypothesis?
larry
What is test statistic. Why do you have to know the distribution of a test statistic?
A test statistic is used to test whether a hypothesis that you have about the underlying distribution of your data is correct or not. The test statistic could be the mean, the variance, the maximum or anything else derived from the observed data. When you know the distribution of the test statistic (under the hypothesis that you want to test) you can find out how probable it was that your test statistic had the value it did have. If this probability is very small, then you reject the hypothesis. The test statistic should be chosen so that under one hypothesis it has one outcome and under the is a summary measure based on the data. It could be the mean, the maximum, the variance or any other statistic. You use a test statistic when you are testing between two hypothesis and the test statistic is one You might think of the test statistic as a single number that summarizes the sample data. Some common test statistics are z-score and t-scores.
What is the conclusion if the test statistic is the same as the critical value?
Any decision based on the test statistic is marginal in such a case. It is important to remember that the test statistic is derived on the basis of the null hypothesis and does not make use of the distribution under the alternative hypothesis.
When can a null hypothesis be rejected?
Usually when the test statistic is in the critical region.
How is the critical region utilized in hypothesis testing?
When you formulate and test a statistical hypothesis, you compute a test statistic (a numerical value using a formula depending on the test). If the test statistic falls in the critical region, it leads us to reject our hypothesis. If it does not fall in the critical region, we do not reject our hypothesis. The critical region is a numerical interval.
What is test statistic?
This is used in statistic to know whether to accept or reject a null hypothesis or alternative hypothesis
Can you accept a null hypothesis under the t statistic and then reject the same null hypothesis using the F statistic?
At the same level of significance and against the same alternative hypothesis, the two tests are equivalent.
What is the basic requirement of a scientific hypothesis?
larry
What is test statistic. Why do you have to know the distribution of a test statistic?
A test statistic is used to test whether a hypothesis that you have about the underlying distribution of your data is correct or not. The test statistic could be the mean, the variance, the maximum or anything else derived from the observed data. When you know the distribution of the test statistic (under the hypothesis that you want to test) you can find out how probable it was that your test statistic had the value it did have. If this probability is very small, then you reject the hypothesis. The test statistic should be chosen so that under one hypothesis it has one outcome and under the is a summary measure based on the data. It could be the mean, the maximum, the variance or any other statistic. You use a test statistic when you are testing between two hypothesis and the test statistic is one You might think of the test statistic as a single number that summarizes the sample data. Some common test statistics are z-score and t-scores.
On average what value is expected for the t statistic when the null hypothesis is true?
When the null hypothesis is true, the expected value for the t statistic is 0. This is because the t statistic is calculated as the difference between the sample mean and the hypothesized population mean, divided by the standard error, and when the null hypothesis is true, these values should be equal, resulting in a t statistic of 0.
What is the rule in hypothesis testing?
The rules are as follows:the hypothesis and its alternative are clearly spelled out before you look at he data,the observations are obtained randomly,the test statistic is based only on the observed data,you have measures of what the likely values of the test statistic if the [null] hypothesis were true and if it were not,you then reject the null hypothesis if the likelihood of obtaining a test statistic which is as or more extreme than observed is smaller than some predetermined (but arbitrary) value. Otherwise you accept the hypothesis.
What is the conclusion if the test statistic is the same as the critical value?
Any decision based on the test statistic is marginal in such a case. It is important to remember that the test statistic is derived on the basis of the null hypothesis and does not make use of the distribution under the alternative hypothesis.
How do you perform a Statistical Hypothesis Testing?
To start with you select your hypothesis and its opposite: the null and alternative hypotheses. You select a confidence level (alpha %), which is the probability that your testing procedure rejects the null hypothesis when, if fact, it is true.Next you select a test statistic and calculate its probability distribution under the two hypotheses. You then find the possible values of the test statistic which, if the null hypothesis were true, would only occur alpha % of the times. This is called the critical region.Carry out the trial and collect data. Calculate the value of the test statistic. If it lies in the critical region then you reject the null hypothesis and go with the alternative hypothesis. If the test statistic does not lie in the critical region then you have no evidence to reject the null hypothesis.
When can a null hypothesis be rejected?
Usually when the test statistic is in the critical region.
How is the critical region utilized in hypothesis testing?
When you formulate and test a statistical hypothesis, you compute a test statistic (a numerical value using a formula depending on the test). If the test statistic falls in the critical region, it leads us to reject our hypothesis. If it does not fall in the critical region, we do not reject our hypothesis. The critical region is a numerical interval.
Would I accept or reject the null hypothesis if the probability of the obtained statistic is 0.001 and alpha is 0.05?
You should reject the null hypothesis.
What is the meaning of null hypthesis being rejected?
You may want to prove that a given statistic of a population has a given value. This is the null hypothesis. For this you take a sample from the population and measure the statistic of the sample. If the result has a small probability of being (say p = .025) if the null hypothesis is correct, then the null hypothesis is rejected (for p = .025) in favor of an alternative hypothesis. This can be simply that the null hypothesis is incorrect.
