Answer:
a
 The null hypothesis is  
The alternative hypothesis  
b
 
c
     The decision rule is  
Fail to reject the null hypothesis
Step-by-step explanation:
From the question we are told that 
   The value given is  
S/N
1       7 5
2      4 3
3      8 7
4      8 8
5      7 9
6      7 5
7      6 5
Generally the sample mean for the first sample  is  mathematically represented as 
         
=>     
=>     
Generally the sample mean for the second sample is mathematically represented as 
         
=>     
=>     
Generally the sample standard deviation  for the first sample  is  mathematically represented as 
            
=>       
=>       
Generally the sample standard deviation  for the second  sample  is  mathematically represented as 
            
=>       
=>       
Generally the pooled standard deviation is  
       
=>    
=>    
The null hypothesis is  
The alternative hypothesis  
Generally the test statistics is mathematically represented as 
       
=>   
=>   
Generally the degree of freedom is mathematically represented as 
      
=>   
=>   
From the t distribution table the probability of   at a degree of freedom of
 at a degree of freedom of  is
 is  
      
Generally the p-value is  
       
From the values  obtained we see that  hence
  hence  
    The decision rule is  
Fail to reject the null hypothesis