What are the hypotheses of the t-test (Null & alternative hypothesis)?

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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