Answer:
The test statistics fall in the critical region and hence null hypothesis is to be rejected.
Step-by-step explanation:
The null hypothesis : H0 : Mean = 6.80  
Alternative hypothesis: Ha: Mean is not equal to 6.80
As per the z statistics  
z = (x’-mean)/(sigma/sqrt n)
Substituting the given values, we get –  
z = 6.4-6.8/(1.1/sqrt 10)
z = -1.149
z test statistics is -1.149
Critical value for two tailed test at 98% confidence is .10749
The test statistics fall in the critical region and hence null hypothesis is to be rejected.
 
        
             
        
        
        
Answer:
14
Step-by-step explanation:
You just multiply 2 to (x + 7) which gets you 2x + 14 and then subtract 2x from 2x seeing as they are like terms and you end up with 14. 
 
        
                    
             
        
        
        
I think the correct answer is A.
        
             
        
        
        
Answer:
16/5
Step-by-step explanation:
3.2 = 3 + 0.2= 3+2/10=3+1/5=16/5
pls mark as brainliest