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# Testing 2 samples - Mean

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Author: Bob Kibler
##### Description:

You will be able to:

• Test claims that compare an average value from 2 independent populations
• determine if a z-test or t-test is the appropriate technique
• the test statistic in a z-test and a t-test are obtained in similar ways, but how the critical value is determined is different
• summarize the results obtained in a non-statistical way

NOTES

• Testing 2 samples follows the same 5 steps as testing 1 sample
• The type of test (z or t) is determined based on the sample size and whether or not the standard deviation of the population is known
• It is important to summarize the results in a non-statistical (easy to understand) way
(more)

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Tutorial

## Example 1 - Ztest

This is a z-test due to a large sample size

## Example 2 - Ztest

This is a z-test due to large samples

## Example 3 - T-test

**This is a t-test due to a small sample size and an unknown standard deviation for the population

## Example 4 (T-test)

**This is a t-test due to a small sample size and an unknown standard deviation for the population