Question

Because sample means were being tested, the ___ is used to calculate the z-score

Answer 1

Formula to calculate Z score

   $Z_{score}=\frac{a-b}{c}$

Where,   a=Population mean

b=Sample Mean

c=Standard Deviation of the sample

Because sample means were being tested, "The Sample Standard Deviation and Population Mean" is used to calculate the z-score

Answer 2

Because sample means were being tested, the bell curve is used to calculate the z-score