Answer:
Let X the random variable that represent the delivery times of a population, and for this case we know the distribution for X is given by:
 
  
Where  and
 and  
Since the distribution of X is normal then we know that the distribution for the sample mean  is given by:
 is given by:
 
And we have;


Step-by-step explanation:
Assuming this question: The delivery times for all food orders at a fast-food restaurant during the lunch hour are normally distributed with a mean of 14.7 minutes and a standard deviation of 3.7 minutes. Let R be the mean delivery time for a random sample of 40 orders at this restaurant. Calculate the mean and standard deviation of  Round your answers to two decimal places.
 Round your answers to two decimal places. 
Previous concepts
Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".
The Z-score is "a numerical measurement used in statistics of a value's relationship to the mean (average) of a group of values, measured in terms of standard deviations from the mean".  
Solution to the problem
Let X the random variable that represent the delivery times of a population, and for this case we know the distribution for X is given by:
 
  
Where  and
 and  
Since the distribution of X is normal then we know that the distribution for the sample mean  is given by:
 is given by:
 
And we have;


 
        
             
        
        
        
Answer:
10.3
Step-by-step explanation:
hope this helps, if any genius answers as well, give brainliest to them
 
        
                    
             
        
        
        
Answer:
13.5
Step-by-step explanation:
12/4=3 
9/3=3 
4.5x3=13.5
 
        
                    
             
        
        
        
Answer:
5x3x2y
Step-by-step explanation:
 
        
             
        
        
        
Answer: The answer would be B) 9% Decrease!
275 - 250 = 25.
25/275 = 0.0909090909
0.0909090909 x 100 = 9.09090909091
Finally you'd round it to 9%.
Therefore there was a 9% decrease in the amount of large pizzas.
Hope this helps (: Stay safe.