Answer:
The critical t-value for such a test given an alpha level of 0.05 is 2.26
Step-by-step explanation:
Null hypothesis : 
Alternate hypothesis :
Population mean = 
Data : 10, 9, 6, 11, 13, 14, 9, 9, 9, and 10
Mean = 
Mean =
Mean =10
Standard deviation : 
Standard deviation :
Standard deviation s :2.144

Df = n-1 = 10-1 = 9
T critical =
T calculated > T critical
So, We failed to accept null hypothesis
Hence the critical t-value for such a test given an alpha level of 0.05 is 2.26