Answer:
C. 5
Step-by-step explanation:
Triangle BED is enlarged by scale factor 4.
(25-x)/4 = x
Multiply both sides by 4.
25-x = 4x
Add x on both sides.
25 = 5x
Divide both sides by 5.
5 = x
Answer:
a. n=4148
b. n=3909
c. The sample size is smaller if a known proportion from prior study is used. The difference in sample sizes is 239
Step-by-step explanation:
a. For sample where no preliminary estimate is given, the minimum sample size is calculated using the formula:

Where:
Margin of error
is the assumed proportion
#Let p=0.5, substitute in the formula to solve for n:

Hence, the minimum sample size is 4148
b. If given a preliminary estimate p=0.38, we use the same formula but substitute p with the given value:

Hence, the minimum sample size is 3909
c. Comparing the sample sizes from a and b:

Hence, the actual sample size is smaller for a known proportion from prior a prior study.