In: Statistics and Probability
The average amount of money spent for lunch per person in the college cafeteria is $6.63 and the standard deviation is $2.54. Suppose that 18 randomly selected lunch patrons are observed. Assume the distribution of money spent is normal, and round all answers to 4 decimal places where possible.
Can i have an actual step by step how to? Already graded.
Solution-:
Let,X- amount of money spent for lunch per person in the college cafeteria
Given: 
 also 

(a) The distribution of X is normal with
 and 
i.e. 
(b) For sample, 
We know the result If 
 then 
 whre, 
 and 
Here, If  
then 
whre, 
 and 

(c) We find, P[that this patron's lunch cost is between $6.812 and $7.3214]


  
  

  
( From Normal Probability Integral table )

Therefore, the required probability is 0.0785.
(d) We ind, P[ that the average lunch cost is between $6.812 and $7.3214 ]
  

  
  
  
  
( From Normal Probability Integral table )
  
Therefore, the required probability is 0.2570.
(e) Yes.