Answer: (7.27%, 7.55%)
Step-by-step explanation:
As per given , we have
Sample size : n= 392
Sample mean : 

Critical two-tailed z-value for 95% confidence = 
Required confidence interval would be :

Hence, the required 95% confidence interval for the mean percentage share of billing volume from network television for the population of all U.S. advertising agencies : (7.27%, 7.55%)
Answer: 33/5
Step-by-step explanation:
6 x 5 = 30
30 + 3 = 33
y=4
the values of x changes while the y doesn't so it's y=4