What are the assumptions for paired and unpaired t-test?

What are the assumptions for paired and unpaired t-test?

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.

What conditions and assumptions are necessary in order to use a paired t-test?

What conditions and assumptions are necessary in order to use a paired t-test? 1.) Paired Data Assumption- The data must be paired, aka the observations are collected in pairs or the observations in one group are naturally related to observations in the other (before and after experiments for example).

Does paired t-test assume independence?

The paired t test assumes that the size of the paired difference is not dependent on the identity of the pair. In particular, the size of the paired difference is assumed to be independent of the size of the first value in the pair.

What are the limitations of t test?

When data violates the assumptions, t-test might not have reliability. Assumptions include: the scale of measurement. The assumption for a t-test is that the scale of measurement applied to the data collected follows a continuous or ordinal scale, such as the scores for an IQ test.

What assumptions are made when conducting a t-test?

The common assumptions made when doing a t-test include those regarding the scale of measurement, random sampling, normality of data distribution, adequacy of sample size and equality of variance in standard deviation.

When should we use a paired t test?

Paired t-tests are used when the same item or group is tested twice, which is known as a repeated measures t-test. Some examples of instances for which a paired t-test is appropriate include: The before and after effect of a pharmaceutical treatment on the same group of people.

What are the assumptions of independent t test?

The assumptions of the t-test for independent means focus on sampling, research design, measurement, population distributions and population variance. The assumptions are listed below. The t-test for independent means is considered typically “robust” for violations of normal distribution.

What is an example of a paired t test?

The paired sample t-test is also called dependent sample t-test. It’s an univariate test that tests for a significant difference between 2 related variables. An example of this is if you where to collect the blood pressure for an individual before and after some treatment, condition, or time point.