What is the difference between Z test and T test? - ProProfs Discuss
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What is the difference between Z-test and T-test?

Asked by Lysa , Last updated: Apr 12, 2024

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7 Answers

E. Austin

E. Austin

E. Austin
E. Austin

Answered Feb 19, 2021

Z- test and t-test are statistical methods use to analyze data applications in science, businesses, and many more. Z-tests are used to test the hypothesis when the population variance is known or when the population variance is not known, but the sample size is large n>30, while t-test is used to test the hypothesis when we do not know the population and the sample size is n<30.

In the z- test, the data are independent, and the normal distribution for z is an average of zero and variance one, while the t-test is also independent, and the sample values are kept accurately. The z-test is based on the normal distribution, while the t-test is based on student t-distribution.

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J. Alva

J. Alva

J. Alva
J. Alva

Answered Jan 29, 2021

Z-test and T-test are standard terms for the statistical testing of the hypothesis in comparing two sample means. The significant difference between the two is that a T-test is used to determine a statistically substantial difference between two sample groups independent in nature. In contrast, Z-test is used to determine the difference between two populations when the variance is provided.

A T-test is ideal for solving problems that have a limited sample size. On the other hand, the Z-test is the hypothesis test that establishes the averages of two sets of information different from one another when provided invariance or standard deviation.

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G. Woods

G. Woods

Traveler and writer by profession.

G. Woods
G. Woods, College student, Graduate, Southampton

Answered Dec 22, 2020

Z−tests are known to be statistical calculations that are normally used when there are population samples that need to be measured. T−tests, on the other hand, are known to be calculations that are used when you need to compare hypotheses.

You would need to use T−tests when you want to make sure that there is a significant difference between the different sample groups that are being measured. Another difference between the two is that you will use the Z−test when you want to compare a large group of people. You would use the T−test when you only want to measure about 30 people and less.

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H. Barnes

H. Barnes

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H. Barnes
H. Barnes, Unemployed, Barnes, Atlanta

Answered Dec 18, 2020

Hypotheses are related to the field of science. They are the beginning of research or an experiment to help understand it. It is also known as educated guesses. There are two types of tests that are used for statistical hypotheses. One is a T-test. This test is very easy to use and is straight to the point.

It is the most used test, which is mainly for that reason. The second type of test is the Z-test. This type of test is used to understand the difference between the means of population and samples. Z-tests are popular to use when there are larger samples, such as samples larger than 30.

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F. Daniel

F. Daniel

I work for a California based MNC.

F. Daniel
F. Daniel, Content Optimization Executive, Diploma in Journalism, California

Answered Dec 15, 2020

One of the major differences between t-test and t-test is that the former is based on a t-statistic, whereas the latter is based on a standard normal distribution. Most researchers use a t-test to compare the means gotten from different sets of data in a bid to check where both differ, most especially when the variance is not known.

In other words, a t-test is a hypothesis test that can be used to check how two independent samples differ by comparing their means. On the other hand, the z-test is also a hypothesis test that you can use to check the difference between two sets of data, most especially when the variance is known. The T-test is based on student t-distribution because it is considered appropriate when the sample size is not large. In contrast, the z-test is based on normal distribution because it is appropriate when the sample size is large, i.e., when the sample size is more than 30.

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W. Pratt

W. Pratt

Want to learn new things and share my knowledge

W. Pratt
W. Pratt, Marketing Analyst, MBA, Lincoln

Answered Aug 04, 2020

T-test and Z-test are two known tests for statistical hypotheses, which are used in solving problems. Let's discuss further. A T-test is actually a statistical hypothesis test. In this kind of text, the student's t-distribution determines the test statistics if the null hypothesis is true. Gossett W. S was the man that primarily introduced the T-statistics under the name "Student."

This, the T-test statistics, is also known as the student T-test. This test is easy to use and also straight forward, which makes it seem to be the most widely used procedure for statistical data analysis testing hypothesis. The Z-test, on the other hand, is usually employed when the standard deviation of the population is known.

The Z-test usually helps to discover if there is any significant difference between the sample and population means. The Z-test is usually used in large samples where n is greater than 30. And some tangible conditions need to have been met before you can use the Z-test.

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A. Samuel

A. Samuel

Writing quality content for contentment has been my passion since i was 21. I've been pursuing it as a Content Manager and Producer.

A. Samuel
A. Samuel, Content Manager, Masters in Marketing and accounting, Florida

Answered Jul 21, 2020

Z-test and T-test are two statistical hypothesis tests out of many other statistical methods that are used to test hypotheses. One of the major differences between the Z-test and T-test is that the former uses a normal distribution, whereas the latter uses a Student's T-distribution.

Z-test is used mostly to compare population and sample and to find out if there is any difference between them. At times, the standard deviation can be used together with Z-tests provided if it is known. T-test seems to be a better statistical method for small samples, i.e., samples less than 30 (n < 30).

In contrast, Z-test is used mostly when the samples to be handled are more than 30, i.e. (n > 30). However, this does not mean that the T-test cannot be used for large samples, just that it is the most suitable statistical method for small samples. In fact, the use of a T-test for large samples makes it look like you are using Z-test.

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