When to use standard error vs standard deviation in z and t-tests?

Charm

New Member
I'm having trouble understanding when is the correct time to use a standard error vs a standard deviation in the denominator in hypothesis testing?
 

shesnaps

New Member
I'm not sure if this is the correct forum but I'm having a problem understanding the difference between the two below.
I'm sure I'm missing something basic here but I appreciate if someone could explain the difference and when I will interpret one over the other.

Thank you.
 

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