Z-test
Z-test
The Z-test is a type of statistical test that determines if there is a significant difference between the means of two groups. It is used when the population variance is known and the sample size is large (typically n > 30). The Z-test is based on the standard normal distribution and is commonly used in hypothesis testing.
Hypothesis Testing
In hypothesis testing, the Z-test is used to test the null hypothesis (H_) against an alternative hypothesis (H_). The null hypothesis typically states that there is no effect or no difference, while the alternative hypothesis suggests that there is an effect or a difference.
The test statistic is calculated using the formula:
- Z = \( \frac{\bar{x} - \mu}{\sigma/\sqrt{n}} \)
where:
- \( \bar{x} \) is the sample mean,
- \( \mu \) is the population mean,
- \( \sigma \) is the population standard deviation,
- \( n \) is the sample size.
Critical Region
The critical region is determined by the significance level (_), which is the probability of rejecting the null hypothesis when it is true. Common significance levels are 0.05, 0.01, and 0.10. The critical value is found from the standard normal distribution table.
If the calculated Z value falls into the critical region, the null hypothesis is rejected in favor of the alternative hypothesis.
Assumptions
The Z-test assumes that:
- The data follows a normal distribution.
- The sample size is large enough for the Central Limit Theorem to apply.
- The population variance is known.
Applications
Z-tests are used in various fields such as medicine, psychology, and economics to compare sample data against known population parameters. They are particularly useful in quality control and clinical trials.
Related Pages
Transform your life with W8MD's budget GLP-1 injections from $125.
W8MD offers a medical weight loss program to lose weight in Philadelphia. Our physician-supervised medical weight loss provides:
- Most insurances accepted or discounted self-pay rates. We will obtain insurance prior authorizations if needed.
- Generic GLP1 weight loss injections from $125 for the starting dose.
- Also offer prescription weight loss medications including Phentermine, Qsymia, Diethylpropion, Contrave etc.
NYC weight loss doctor appointments
Start your NYC weight loss journey today at our NYC medical weight loss and Philadelphia medical weight loss clinics.
- Call 718-946-5500 to lose weight in NYC or for medical weight loss in Philadelphia 215-676-2334.
- Tags:NYC medical weight loss, Philadelphia lose weight Zepbound NYC, Budget GLP1 weight loss injections, Wegovy Philadelphia, Wegovy NYC, Philadelphia medical weight loss, Brookly weight loss and Wegovy NYC
WikiMD's Wellness Encyclopedia |
Let Food Be Thy Medicine Medicine Thy Food - Hippocrates |
Medical Disclaimer: WikiMD is not a substitute for professional medical advice. The information on WikiMD is provided as an information resource only, may be incorrect, outdated or misleading, and is not to be used or relied on for any diagnostic or treatment purposes. Please consult your health care provider before making any healthcare decisions or for guidance about a specific medical condition. WikiMD expressly disclaims responsibility, and shall have no liability, for any damages, loss, injury, or liability whatsoever suffered as a result of your reliance on the information contained in this site. By visiting this site you agree to the foregoing terms and conditions, which may from time to time be changed or supplemented by WikiMD. If you do not agree to the foregoing terms and conditions, you should not enter or use this site. See full disclaimer.
Credits:Most images are courtesy of Wikimedia commons, and templates, categories Wikipedia, licensed under CC BY SA or similar.
Contributors: Prab R. Tumpati, MD