So, what are the hypotheses of the t-test?

One sample t-test
Null hypothesis: The sample mean is equal to the reference value.
Alternative hypothesis: The sample mean is unequal to the reference value.

Independent samples t-test
Null hypothesis: The mean values in both groups are the same.
Alternative hypothesis: The mean values in both groups are not equal.

Paired samples t-test
Null hypothesis: The mean of the difference between the pairs is zero.
Alternative hypothesis: The mean of the difference between the pairs is not zero.

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https://datatab.net/tutorial/one-samp...

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https://datatab.net/tutorial/unpaired...

► t-Test for dependent samples:
https://datatab.net/tutorial/paired-t...

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