SITEMAP ABOUT
MiC Quality

SIX SIGMA GLOSSARY

  PROCESS IMPROVEMENT AND SIX SIGMA
ONLINE COURSES FREE TRIAL SIX SIGMA FAQ BROCHURES LICENSES ENROLL
GLOSSARY
:: Online Courses
:: Free Trial
:: Six Sigma
>> Glossary
>> Calculators
>> Reference Tables
>> Book Reviews
>> Black Belt ASQ
:: FAQ
:: Brochures
:: Licenses
:: Discounts
 
Welcome to MiC Quality Six Sigma Resources
Online Course Instructor
Glen Netherwood
MiC Quality
Online Learning
:: Home ::Six Sigma ::SIX SIGMA GLOSSARY: z-Test :: CURRENT STUDENTS LOGIN

[SIX SIGMA GLOSSARY ALPHABETICAL INDEX] [SIX SIGMA GLOSSARY INDEX OF TOPICS]

z-Test
 

The z-test is a hypothesis test used to test the mean against a specified value. The z-test is used where the standard deviation is known or the sample is large (greater than about 30). The population must also conform to a normal distribution. The hypothesis is:

H0 the population mean equals a specified value
H1 the popular mean is [equal to/less than/greater than] a specified value

The test is:

where:

sample mean
μ 0 specified value
s sample standard deviation
n sample size

The p-value can be obtained from Excel using the function:

one-tail test: = 1 - NORMSDIST(Z0)
two-tail test: = (1 - NORMSDIST(Z0))/2

Alternatively the critical values of the z statistic can be found from tables. For a one sided test:

α
0.10
0.05
0.025
0.01
Zα
1.28
1.64
1.96
2.33

For samples less than 30 use the t-test.

 

Analytical and descriptive statistics are covered in the MiC Quality online course Primer in Statistics.

Try out our courses by taking the first module of the Primer in Statistics free of charge.

  Enroll Now
[SIX SIGMA GLOSSARY ALPHABETICAL INDEX] [SIX SIGMA GLOSSARY INDEX OF TOPICS] [Top]

MiC Quality Courses
:: Six Sigma Primer
:: Primer in Statistics
:: Advanced Statistics
:: Statistical Process Control SPC
:: Advanced SPC
:: Design of Experiments
:: Advanced DOE
:: Measurement Systems Analysis MSA/ Gage R&R
   
Primer in Statistics
FREE First Module
"Introduction to Statistics"

PDF

Primer in Statistics
FREE Reference Booklet

FREE Excel Primer
   
Learn More



 
Copyright 1998-2014 MiC Quality Legal Notices and Privacy Policy