Answer:
25%
Step-by-step explanation:
From the boxplot Given, an earning of $25 or less is represented on the boxplot as the lower quartile of the distribution which is the point at the start of the box. The lower quartile value is the percentage value up to 25% that is the first 25% of the distribution.
Hence, the percentage required = 25%
Hence, Nicholas earned $25 or less about 25% of the time.
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:
#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.