The value of the z-score for x = 21 is 0
Here, we want to find the value of the z-score
We use the following formula;
[tex]z-\text{score = }\frac{x-\operatorname{mean}}{SD}[/tex]In this case, x = 21, mean = 21 and SD = 1.2
Substituting these values, we have that;
[tex]z-\text{score = }\frac{21-21}{1.2}\text{ = }\frac{0}{1.2}\text{ = 0}[/tex]