Answer:
The Alpha Level
Explanation:
The critical value is obtained by applying the alpha value to an area. For example if we choose the alpha level of 0.05 the critical value would be 1.96 for a two tailed test. But if the alpha is 0.1 the critical value would be 1.645 and similarly the critical value would be 2.58 for 0.01 alpha level.
The critcal value depends on the alpha level and is set accordingly depending on one tailed or tailed test. It does not involve the use of The Obtained Statistic or The Population Mean.