Answer:
z = - 1
Step-by-step explanation:
Given
- 18 = 9z - 9 ( add 9 to both sides )
- 9 = 9z ( divide both sides by 9 )
- 1 = z
Try this option (see the attached picture).
Answer:
And rounded up we have that n=1068
Step-by-step explanation:
For this case we have the following info given:
the margin of error desired
the level of confidence given
The margin of error for the proportion interval is given by this formula:
(a)
the critical value for 95% of confidence is 
We can use as estimator for the population of interest
. And on this case we have that
and we are interested in order to find the value of n, if we solve n from equation (a) we got:
(b)
And replacing into equation (b) the values from part a we got:
And rounded up we have that n=1068
Answer: 4 gallons = 15 liters, 8 liters = 2 gallons, 12.5 liters = 3 gallons, and 6 gallons = 23 liters.