Answer:
Test statistic is 0.67
Critical value is -2.33
Step-by-step explanation:
Consider the provided information.
The formula for testing a proportion is based on the z statistic.

Were  is sample proportion.
 is sample proportion.
 hypothesized proportion and n is the smaple space,
 hypothesized proportion and n is the smaple space, 
Random sample of 100 adults, 12% say that they own a smart watch.
A company claims that less than 10% of adults own a smart watch.
Therefore, n = 100   = 0.12
,
 = 0.12
,  = 0.10
 = 0.10

Substitute the respective values in the above formula.


Hence, test statistic = 0.67
This is the left tailed test.
Now using the table the P value is:
P(z < 0.667) = 0.7476
P-value = 0.7476

Here,  P-value > α therefore, we are fail to reject the null hypothesis.

Hence, Critical value is -2.33