What does it mean to say that random samples are independent? Random samples gathered in such a way that the selection of a particular case for one sample has no effect on the probability that any other particular case will be selected for the other samples. the populations from which the sample was drawn are the same.
What is null and alternative hypothesis?
A null hypothesis is a type of conjecture used in statistics that proposes that there is no difference between certain characteristics of a population or data-generating process. The alternative hypothesis proposes that there is a difference .
When testing for the significance of the difference between two sample means the null hypothesis is that quizlet?
When testing for the significance of the difference between two samples, the null hypothesis states that the____________ are the same . populations from which the samples are drawn are different on the trait of interest. the difference in sample means. combines information from two samples.
What does a higher alpha level mean?
Higher values of α make it easier to reject the null hypothesis , so choosing higher values for α can reduce the probability of a Type II error. The consequence here is that if the null hypothesis is true, increasing α makes it more likely that we commit a Type I error (rejecting a true null hypothesis).
What does the null hypothesis say about the difference between two sample means?
Says that the difference between two sample means is created merely by chance errors created by random sampling. There is no true difference. What does the null hypothesis say about the difference between two sample means? No FAIL to reject the Null hypothesis because p>0.05.
What is an alternative hypothesis example?
The alternate hypothesis is just an alternative to the null . For example, if your null is “I’m going to win up to $1,000” then your alternate is “I’m going to win $1,000 or more.” Basically, you’re looking at whether there’s enough change (with the alternate hypothesis) to be able to reject the null hypothesis.
How do you choose the null and alternative hypothesis?
You want your alternate hypothesis to come from the new model under test, and the null hypothesis to be from a different model. The null hypothesis should come from a model which others would choose to use when challenging your scientific claims!
What is implied by the rejection of the null hypothesis in the two-sample case?
What does rejection of the null hypothesis in the two-sample case imply about the populations from which the samples are drawn? They are statistically significant, their is a difference . ... Since the sample means are the same value, there is no need to conduct any tests; these results cannot be significant.
When comparing two-sample means we can safely reject the null hypothesis if?
The null hypothesis will be rejected if the difference between sample means is bigger than would be expected by chance . Formulate an analysis plan. For this analysis, the significance level is 0.05. Using sample data, we will conduct a two-sample t-test of the null hypothesis.
What is the significance level of a hypothesis test?
The significance level, also denoted as alpha or α, is the probability of rejecting the null hypothesis when it is true . For example, a significance level of 0.05 indicates a 5% risk of concluding that a difference exists when there is no actual difference.
What are the three levels of significance?
Popular levels of significance are 10% (0.1), 5% (0.05), 1% (0.01), 0.5% (0.005), and 0.1% (0.001) . If a test of significance gives a p-value lower than or equal to the significance level, the null hypothesis is rejected at that level.
Is p-value same as Alpha?
Alpha sets the standard for how extreme the data must be before we can reject the null hypothesis. The p-value indicates how extreme the data are.
What does an alpha level of .05 mean?
An alpha level of . 05 means that you are willing to accept up to a 5% chance of rejecting the null hypothesis when the null hypothesis is actually true . ... This number reflects the probability of obtaining results as extreme as what you obtained in your sample if the null hypothesis was true.
How do you compare two sample means?
- Independent Samples T-Test. ...
- One sample T-Test. ...
- Paired Samples T-Test. ...
- One way Analysis of Variance (ANOVA).
What is a Type 1 error example?
Examples of Type I Errors
For example, let’s look at the trail of an accused criminal. The null hypothesis is that the person is innocent, while the alternative is guilty. A Type I error in this case would mean that the person is not found innocent and is sent to jail , despite actually being innocent.
What is the null hypothesis for a 2 sample t-test?
The default null hypothesis for a 2-sample t-test is that the two groups are equal . You can see in the equation that when the two groups are equal, the difference (and the entire ratio) also equals zero.
