Answer:
 
      
 
  
If we compare the p value and the significance level given for example  we see that
 we see that  so we can conclude that we reject the null hypothesis, and the true mean is significant higher than 24 years.
 so we can conclude that we reject the null hypothesis, and the true mean is significant higher than 24 years.   
Step-by-step explanation:
1) Data given and notation      
 represent the sample mean
 represent the sample mean      
 represent the standard deviation for the sample
 represent the standard deviation for the sample      
 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 (variable of interest)      
 represent the p value for the test (variable of interest)
 represent the p value for the test (variable of interest)  
Confidence =0.95 or 95%

State the null and alternative hypotheses.      
We need to conduct a hypothesis in order to determine if the mean is higher than 24, the system of hypothesis would be:      
Null hypothesis: 
      
Alternative hypothesis: 
      
We don't know the population deviation, so for this case is better apply a t test to compare the actual mean to the reference value, and the statistic is given by:      
 (1)
 (1)      
t-test: "Is used to compare group means. Is one of the most common tests and is used to determine if the mean is (higher, less or not equal) to an specified value".  
Calculate the statistic      
We can replace in formula (1) the info given like this:      
 
      
Calculate the P-value      
First we need to calculate the degrees of freedom given by:  
 
  
Since is a one-side upper test the p value would be:      
 
  
Conclusion      
If we compare the p value and the significance level given for example  we see that
 we see that  so we can conclude that we reject the null hypothesis, and the true mean is significant higher than 24 years.
 so we can conclude that we reject the null hypothesis, and the true mean is significant higher than 24 years.