What are the conditions for a paired t-test?

What are the conditions for a paired t-test?

The paired sample t-test has four main assumptions:

• The dependent variable must be continuous (interval/ratio).
• The observations are independent of one another.
• The dependent variable should be approximately normally distributed.
• The dependent variable should not contain any outliers.

What is a difference score for a paired samples t-test?

Here μ is the population mean of the difference scores, and μ0 is the population mean of the difference scores according to the null hypothesis, which is usually 0. A difference score is the difference between the first score of a pair and the second score of a pair.

What is a paired sample t-test and when is it used?

A paired t-test is used when we are interested in the difference between two variables for the same subject. Often the two variables are separated by time. For example, in the Dixon and Massey data set we have cholesterol levels in 1952 and cholesterol levels in 1962 for each subject.

What type of data are required for the paired samples t-test?

Data Requirements

• Dependent variable that is continuous (i.e., interval or ratio level)
• Related samples/groups (i.e., dependent observations)
• Random sample of data from the population.
• Normal distribution (approximately) of the difference between the paired values.

Why is a paired t-test more powerful?

Paired t-tests are considered more powerful than unpaired t-tests because using the same participants or item eliminates variation between the samples that could be caused by anything other than what’s being tested.

What is the purpose of a paired t-test?

The paired t-test is a method used to test whether the mean difference between pairs of measurements is zero or not.

How do you interpret a paired samples t test?

Complete the following steps to interpret a paired t-test….

1. Step 1: Determine a confidence interval for the population mean difference. First, consider the mean difference, and then examine the confidence interval.
2. Step 2: Determine whether the difference is statistically significant.
3. Step 3: Check your data for problems.

Is there a paired Z test?

The paired z-test may be used to test whether the mean difference of two populations is greater than, less than, or not equal to 0. Because the standard normal distribution is used to calculate critical values for the test, this test is often called the paired z-test.

What’s the difference between a paired t test and unpaired?

A paired t-test is designed to compare the means of the same group or item under two separate scenarios. An unpaired t-test compares the means of two independent or unrelated groups. In an unpaired t-test, the variance between groups is assumed to be equal. In a paired t-test, the variance is not assumed to be equal.

When do you not use a paired t test?

Here’s a simple rule to determine if the paired t must not be used – if a given data point in group one could be paired with any data point in group two, you cannot use a paired t test Examples

When to use independent test in paired samples?

The number of points in each data set must be the same, and they must be organized in pairs, in which there is a definite relationship between each pair of data points If the data were taken as random samples, you must use the independent test even if the number of data points in each set is the same

What is the formula for a paired sample t test?

Paired Samples t-test: Formula. A paired samples t-test always uses the following null hypothesis: H 0: μ 1 = μ 2 (the two population means are equal) The alternative hypothesis can be either two-tailed, left-tailed, or right-tailed: H 1 (two-tailed): μ 1 ≠ μ 2 (the two population means are not equal)

When to use the Student’s t test?

‘Student’s’ t Test (For Paired Samples) Use this test to compare two small sets of quantitative data when data in each sample set are related in a special way. Criteria The number of points in each data set must be the same, and they must be organized in pairs, in which there is a definite relationship between each pair…