Answer:
 
    
Critical value
The significance is 5% so then  and
 and  then the critical value for this case would be
 then the critical value for this case would be  . Since the calculated value is higher than the critical value we have enough evidence to reject the null hypothesis and we can conclude that the true mean is higher than 10 mg
. Since the calculated value is higher than the critical value we have enough evidence to reject the null hypothesis and we can conclude that the true mean is higher than 10 mg
P value
The p value would be given 
 
  
Since the p value is lower than the significance level we have enough evidence to reject the null hypothesis and we can conclude that the true mean is significantly higher than 10 mg
Step-by-step explanation:
Information given
 represent the sample mean
 represent the sample mean
 represent the population standard deviation
 represent the population standard deviation 
 sample size
 sample size  
 represent the value that we want to test
 represent the value that we want to test
 represent the significance level for the hypothesis test.
 represent the significance level for the hypothesis test.  
t would represent the statistic 
 represent the p value
 represent the p value
Hypothesis to test 
We want to test if the true mean is higher than 10mg, the system of hypothesis would be:  
Null hypothesis: 
  
Alternative hypothesis: 
  
the statistic for this case would be given by:
 (1)
  (1)  
Replacing we got:
 
    
Critical value
The significance is 5% so then  and
 and  then the critical value for this case would be
 then the critical value for this case would be  . Since the calculated value is higher than the critical value we have enough evidence to reject the null hypothesis and we can conclude that the true mean is higher than 10 mg
. Since the calculated value is higher than the critical value we have enough evidence to reject the null hypothesis and we can conclude that the true mean is higher than 10 mg
P value
The p value would be given 
 
  
Since the p value is lower than the significance level we have enough evidence to reject the null hypothesis and we can conclude that the true mean is significantly higher than 10 mg