Table of Contents

## What is a 2 sample test of means?

The two-sample t-test (Snedecor and Cochran, 1989) is used to determine if two population means are equal. A common application is to test if a new process or treatment is superior to a current process or treatment. There are several variations on this test. The data may either be paired or not paired.

**What is an example of a two sample test?**

Two Sample t-test: Motivation Suppose we want to know whether or not the mean weight between two different species of turtles is equal. Since there are thousands of turtles in each population, it would be too time-consuming and costly to go around and weigh each individual turtle.

**What is a two sample procedure?**

A two-sample procedure is given for selecting the population with the largest mean fromk normal populations with known variances. Thek populations are screened through the first sample for possible elimination of those populations which have considerably smaller means.

### What are the 2 types of two sample t tests?

Independent two-sample t-test. Paired sample t-test.

**How do you perform a two-sample t-test?**

Steps to Calculate Two Sample T Hypothesis Test (Unequal Variance):

- Step 1 – Calculate mean (X̅) of each sample. X̅ = (x1 + x2 + ….
- Step 2 – Calculate variance (S2) of each sample.
- Step 3 – Calculate t value.
- Step 4 – Calculate degrees of freedom (DF)
- Step 5 – Compare t-calc with critical value in the t-distribution table.

**What is the difference between paired data and data from two samples?**

Two-sample t-test is used when the data of two samples are statistically independent, while the paired t-test is used when data is in the form of matched pairs.

## What is the difference between one sample and two sample test?

If you are studying one group, use a paired t-test to compare the group mean over time or after an intervention, or use a one-sample t-test to compare the group mean to a standard value. If you are studying two groups, use a two-sample t-test. If you want to know only whether a difference exists, use a two-tailed test.

**What is the difference between a one sample test and a two sample test?**

**What is the difference between two independent samples and paired samples?**

Paired-samples t tests compare scores on two different variables but for the same group of cases; independent-samples t tests compare scores on the same variable but for two different groups of cases.

### Why Z-test is used?

A z-test is a statistical test used to determine whether two population means are different when the variances are known and the sample size is large.

**How to perform a 2-sample t-test?**

The consultant performs a 2-sample t-test to determine whether there is a difference in the patient ratings between the hospitals. Open the sample data, HospitalComparison.MTW. Choose Stat > Basic Statistics > 2-Sample t.

**What is the difference between a 1-sample t-test and a paired t- test?**

The paired t-test and the 1-sample t-test are actually the same test in disguise! As we saw above, a 1-sample t-test compares one sample mean to a null hypothesis value. A paired t-test simply calculates the difference between paired observations (e.g., before and after) and then performs a 1-sample t-test on the differences.

## What is the difference between a 2-sample t-test and Minitab t-test?

In a 2-sample t-test, the denominator is still the noise, but Minitab can use two different values. You can either assume that the variability in both groups is equal or not equal, and Minitab uses the corresponding estimate of the variability.