The luncheon expense vouchers of the executives of a large a

The luncheon expense vouchers of the executives of a large advertising firm have a population mean = $10 per person and = $4 per person.

a)     Below what dollar value will 99% of the sample means fall?_______

b)    What proportion of the sample means will be between $8 and $12?     _______      

c)        What proportion of the sample means will be below $8 or above $12?               _______        

d)      What proportion of the sample means will be below $8?                             _______

e)              What proportion of the sample means will be above $13?

Solution

1-0.99=0.01

z=2.32

2.32= x -10 / 4

19.28

b)

8/10 + 12/10 = 2

c)

2-1 = 1

d)

8/10 + 4 =4.8

e)

13/10 +4 =5.3