Statistics Help Question 5 and 6 please if you could explain

Statistics Help!

Question 5 and 6 please

if you could explain how you got the answers as well

Solution

Mean ( u ) =4750
Standard Deviation ( sd )=18839.785
Number ( n ) = 2500
Normal Distribution = Z= X- u / (sd/Sqrt(n) ~ N(0,1)                  

a)
P(X > 6000) = (6000-4750)/18839.785/ Sqrt ( 2500 )
= 1250/376.796= 3.3174
= P ( Z >3.3174) From Standard Normal Table
= 0.0005                  
      
b)P(X > 7000) = (7000-4750)/18839.785/ Sqrt ( 2500 )
= 2250/376.796= 5.9714
= P ( Z >5.9714) From Standard Normal Table
= 0                  

Rate of such pay out is an outlier