Answer:
 
    
 
  
If we compare the p value and the significance level given  we see that
 we see that  so we can conclude that we have enough evidence to reject the null hypothesis,and we have enough evidence to conclude that the true mean is significantly lower thn 4.8 at 10% of signficance.
 so we can conclude that we have enough evidence to reject the null hypothesis,and we have enough evidence to conclude that the true mean is significantly lower thn 4.8 at 10% of signficance.  
Step-by-step explanation:
Data given and notation  
 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. 
z 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)  
State the null and alternative hypotheses.  
We need to conduct a hypothesis in order to check if thetrue mean is below the specifications, the system of hypothesis would be:  
Null hypothesis: 
  
Alternative hypothesis: 
  
If we analyze the size for the sample is > 30 and we know the population deviation so is better apply a z test to compare the actual mean to the reference value, and the statistic is given by:  
 (1)
  (1)  
z-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:  
 
    
P-value
Since is a one sided test the p value would be:  
 
  
Conclusion  
If we compare the p value and the significance level given  we see that
 we see that  so we can conclude that we have enough evidence to reject the null hypothesis,and we have enough evidence to conclude that the true mean is significantly lower thn 4.8 at 10% of signficance.
 so we can conclude that we have enough evidence to reject the null hypothesis,and we have enough evidence to conclude that the true mean is significantly lower thn 4.8 at 10% of signficance.